A new company is offering mtDNA/Y-chromosome tests at $197 each.
September 30, 2004
Handsome, not high-status men get the girl
It has been commonly assumed that men prefer beautiful women and women prefer powerful men. According to this study, women and men actually both prefer good looking people rather than high-status people of the opposite sex.
Anthropol Anz. 2003 Sep;61(3):331-41.
Results of an explorative empirical study on human mating in Germany: handsome men, not high-status men, succeed in courtship.
Pashos A et al.
Recent research on human mating depicts men as searching for physical attractiveness (PA) and women as searching for status. To identify the mechanisms which lead to universal, biologically interpretable structures in social processes, we focused on the proximate causes for inter- and intrasexual differences in human mating preferences, attraction, and tactics. We collected data on 180 young singles (mean age 26.9 years) without a steady relationship. A questionnaire and a video sequence (20-30 seconds) of each subject was taken. Next, each video sequence was rated by approximately 20 individuals of the opposite sex, who also participated in this study. Surprisingly, the answers given by male and female subjects regarding sociosexual behaviour and mating preferences are predominantly congruent. Sex differences among preferences for good looking and high-status partners were small or even insignificant. Lower educated subjects had considerably higher status preferences than higher educated individuals. In both sexes, PA was much more preferred in a potential partner than status. For both sexes, physical appearance was decisive for the subject's dating attractiveness. Male, but not female dating attractiveness also correlates with a kind and charismatic appearance. Furthermore, there was a positive linear relationship between men's PA and their number of sexual partners within the last year. Men with more than four sexual partners were all above-average in PA, while the most attractive women had a medium number of sexual partners. However, in this respect, status had no influence. The results show that sex differences in mating are more complex than hitherto assumed.
Link
Anthropol Anz. 2003 Sep;61(3):331-41.
Results of an explorative empirical study on human mating in Germany: handsome men, not high-status men, succeed in courtship.
Pashos A et al.
Recent research on human mating depicts men as searching for physical attractiveness (PA) and women as searching for status. To identify the mechanisms which lead to universal, biologically interpretable structures in social processes, we focused on the proximate causes for inter- and intrasexual differences in human mating preferences, attraction, and tactics. We collected data on 180 young singles (mean age 26.9 years) without a steady relationship. A questionnaire and a video sequence (20-30 seconds) of each subject was taken. Next, each video sequence was rated by approximately 20 individuals of the opposite sex, who also participated in this study. Surprisingly, the answers given by male and female subjects regarding sociosexual behaviour and mating preferences are predominantly congruent. Sex differences among preferences for good looking and high-status partners were small or even insignificant. Lower educated subjects had considerably higher status preferences than higher educated individuals. In both sexes, PA was much more preferred in a potential partner than status. For both sexes, physical appearance was decisive for the subject's dating attractiveness. Male, but not female dating attractiveness also correlates with a kind and charismatic appearance. Furthermore, there was a positive linear relationship between men's PA and their number of sexual partners within the last year. Men with more than four sexual partners were all above-average in PA, while the most attractive women had a medium number of sexual partners. However, in this respect, status had no influence. The results show that sex differences in mating are more complex than hitherto assumed.
Link
Most recent common ancestor of living humans lived in 300BC
Nature 431, 562 - 566 (30 September 2004); doi:10.1038/nature02842
Modelling the recent common ancestry of all living humans
DOUGLAS L. T. ROHDE et al.
If a common ancestor of all living humans is defined as an individual who is a genealogical ancestor of all present-day people, the most recent common ancestor (MRCA) for a randomly mating population would have lived in the very recent past1-3. However, the random mating model ignores essential aspects of population substructure, such as the tendency of individuals to choose mates from the same social group, and the relative isolation of geographically separated groups. Here we show that recent common ancestors also emerge from two models incorporating substantial population substructure. One model, designed for simplicity and theoretical insight, yields explicit mathematical results through a probabilistic analysis. A more elaborate second model, designed to capture historical population dynamics in a more realistic way, is analysed computationally through Monte Carlo simulations. These analyses suggest that the genealogies of all living humans overlap in remarkable ways in the recent past. In particular, the MRCA of all present-day humans lived just a few thousand years ago in these models. Moreover, among all individuals living more than just a few thousand years earlier than the MRCA, each present-day human has exactly the same set of genealogical ancestors.
...
These estimates would suggest, with the exchange of just one pair of migrants per generation between large panmictic populations of realistic size, that the MRCA appears in about the year 300 BC, and all modern individuals have identical ancestors by about 3,000 BC. Such estimates are extremely tentative, and the model contains several obvious sources of error, as it was motivated more by considerations of theoretical insight and tractability than by realism. Its main message is that substantial forms of population subdivision can still be compatible with very recent common ancestors.
Link
Modelling the recent common ancestry of all living humans
DOUGLAS L. T. ROHDE et al.
If a common ancestor of all living humans is defined as an individual who is a genealogical ancestor of all present-day people, the most recent common ancestor (MRCA) for a randomly mating population would have lived in the very recent past1-3. However, the random mating model ignores essential aspects of population substructure, such as the tendency of individuals to choose mates from the same social group, and the relative isolation of geographically separated groups. Here we show that recent common ancestors also emerge from two models incorporating substantial population substructure. One model, designed for simplicity and theoretical insight, yields explicit mathematical results through a probabilistic analysis. A more elaborate second model, designed to capture historical population dynamics in a more realistic way, is analysed computationally through Monte Carlo simulations. These analyses suggest that the genealogies of all living humans overlap in remarkable ways in the recent past. In particular, the MRCA of all present-day humans lived just a few thousand years ago in these models. Moreover, among all individuals living more than just a few thousand years earlier than the MRCA, each present-day human has exactly the same set of genealogical ancestors.
...
These estimates would suggest, with the exchange of just one pair of migrants per generation between large panmictic populations of realistic size, that the MRCA appears in about the year 300 BC, and all modern individuals have identical ancestors by about 3,000 BC. Such estimates are extremely tentative, and the model contains several obvious sources of error, as it was motivated more by considerations of theoretical insight and tractability than by realism. Its main message is that substantial forms of population subdivision can still be compatible with very recent common ancestors.
Link
Cereal production 23,000 years ago
Researchers find signs of grain milling, baking 23,000 years ago
New find in Israel shows that cereal production predates agricultural societies by millennia
Archaeologists have found strong evidence that wheat and barley were refined into cereals 23,000 years ago, suggesting that humans were processing grains long before hunter-gatherer societies developed agriculture. The findings, including the identification of the earliest known oven and hence the oldest evidence of baking, were described in a recent issue of the journal Nature. "This is an observation of key progress in human society, as the beginning of baking was likely a major step forward in nutrition," says author Ehud Weiss, a postdoctoral researcher in Harvard University’s Department of Anthropology and Peabody Museum. "Our work also provides evidence that ancient people held important knowledge that survives to this day. Ten thousand years before agriculture developed, humans recognized the value of cereals."
Full story
New find in Israel shows that cereal production predates agricultural societies by millennia
Archaeologists have found strong evidence that wheat and barley were refined into cereals 23,000 years ago, suggesting that humans were processing grains long before hunter-gatherer societies developed agriculture. The findings, including the identification of the earliest known oven and hence the oldest evidence of baking, were described in a recent issue of the journal Nature. "This is an observation of key progress in human society, as the beginning of baking was likely a major step forward in nutrition," says author Ehud Weiss, a postdoctoral researcher in Harvard University’s Department of Anthropology and Peabody Museum. "Our work also provides evidence that ancient people held important knowledge that survives to this day. Ten thousand years before agriculture developed, humans recognized the value of cereals."
Full story
Dating the oldest biblical verses c. 600BC
The New York Times report on the earliest evidence of Biblical verses. An article on the same topic by Ha'aretz.
September 28, 2004
Ethiopian and Yemeni mtDNA
A new paper presents a very detailed view of mtDNA variation in Ethiopia and Yemen. In agreement with previous genetic work and traditional physical anthropology, which saw Ethiopians as representatives of a subequatorial "Ethiopid" race combining Caucasoid and Negroid characters, this new research affirms the "intermediate" composition of the Ethiopian gene pool:
Am. J. Hum. Genet., 75:000, 2004
Ethiopian Mitochondrial DNA Heritage: Tracking Gene Flow across and around the Gate of Tears
Toomas Kivisild et al.
Approximately 10 miles separate the Horn of Africa from the Arabian Peninsula at Bab-el-Mandeb (the Gate of Tears). Both historic and archaeological evidence indicate tight cultural connections, over millennia, between these two regions. High-resolution phylogenetic analysis of 270 Ethiopian and 115 Yemeni mitochondrial DNAs was performed in a worldwide context, to explore gene flow across the Red and Arabian Seas. Nine distinct subclades, including three newly defined ones, were found to characterize entirely the variation of Ethiopian and Yemeni L3 lineages. Both Ethiopians and Yemenis contain an almost-equal proportion of Eurasian-specific M and N and African-specific lineages and therefore cluster together in a multidimensional scaling plot between Near Eastern and sub-Saharan African populations. Phylogeographic identification of potential founder haplotypes revealed that approximately one-half of haplogroup L0–L5 lineages in Yemenis have close or matching counterparts in southeastern Africans, compared with a minor share in Ethiopians. Newly defined clade L6, the most frequent haplogroup in Yemenis, showed no close matches among 3,000 African samples. These results highlight the complexity of Ethiopian and Yemeni genetic heritage and are consistent with the introduction of maternal lineages into the South Arabian gene pool from different source populations of East Africa. A high proportion of Ethiopian lineages, significantly more abundant in the northeast of that country, trace their western Eurasian origin in haplogroup N through assorted gene flow at different times and involving different source populations.
Link
Though present-day Ethiopia is a land of great ethnic diversity, the majority of Ethiopians speak different Semitic, Cushitic, and Omotic languages that belong to the Afro-Asiatic linguistic phylum. Maternal lineages of Semitic- (Amharic, Tigrinya, and Gurage) and Cushitic- (Oromo and Afar) speaking populations studied here reveal that their mtDNA pool is a nearly equal composite of sub-Saharan and western Eurasian lineages. This finding, consistent with classic genetic-marker studies (Cavalli-Sforza 1997) and previous mtDNA results, is also in agreement with a similarly high proportion of western Asian Y chromosomes in Ethiopians (Passarino et al. 1998; Semino et al. 2002), which supports the view (Richards et al. 2003) that the observed admixture between sub-Saharan African and, most probably, western Asian ancestors of the Ethiopian populations applies to their gene pool in general.
Am. J. Hum. Genet., 75:000, 2004
Ethiopian Mitochondrial DNA Heritage: Tracking Gene Flow across and around the Gate of Tears
Toomas Kivisild et al.
Approximately 10 miles separate the Horn of Africa from the Arabian Peninsula at Bab-el-Mandeb (the Gate of Tears). Both historic and archaeological evidence indicate tight cultural connections, over millennia, between these two regions. High-resolution phylogenetic analysis of 270 Ethiopian and 115 Yemeni mitochondrial DNAs was performed in a worldwide context, to explore gene flow across the Red and Arabian Seas. Nine distinct subclades, including three newly defined ones, were found to characterize entirely the variation of Ethiopian and Yemeni L3 lineages. Both Ethiopians and Yemenis contain an almost-equal proportion of Eurasian-specific M and N and African-specific lineages and therefore cluster together in a multidimensional scaling plot between Near Eastern and sub-Saharan African populations. Phylogeographic identification of potential founder haplotypes revealed that approximately one-half of haplogroup L0–L5 lineages in Yemenis have close or matching counterparts in southeastern Africans, compared with a minor share in Ethiopians. Newly defined clade L6, the most frequent haplogroup in Yemenis, showed no close matches among 3,000 African samples. These results highlight the complexity of Ethiopian and Yemeni genetic heritage and are consistent with the introduction of maternal lineages into the South Arabian gene pool from different source populations of East Africa. A high proportion of Ethiopian lineages, significantly more abundant in the northeast of that country, trace their western Eurasian origin in haplogroup N through assorted gene flow at different times and involving different source populations.
Link
September 27, 2004
Clinal vs. racial model of human genetic variation
A reader alerted me to this recent article on the subject of how human genetic variation is best described. I'll comment on it later on, but it is definitely worth reading, as it poses a sophisticated challenge to the concept of race - unlike many other heavily politicized writings on the subject.
Genome Research 14:1679-1685, 2004
Evidence for Gradients of Human Genetic Diversity Within and Among Continents
David Serre et al.
Genetic variation in humans is sometimes described as being discontinuous among continents or among groups of individuals, and by some this has been interpreted as genetic support for "races." A recent study in which >350 microsatellites were studied in a global sample of humans showed that they could be grouped according to their continental origin, and this was widely interpreted as evidence for a discrete distribution of human genetic diversity. Here, we investigate how study design can influence such conclusions. Our results show that when individuals are sampled homogeneously from around the globe, the pattern seen is one of gradients of allele frequencies that extend over the entire world, rather than discrete clusters. Therefore, there is no reason to assume that major genetic discontinuities exist between different continents or "races."
Link
Genome Research 14:1679-1685, 2004
Evidence for Gradients of Human Genetic Diversity Within and Among Continents
David Serre et al.
Genetic variation in humans is sometimes described as being discontinuous among continents or among groups of individuals, and by some this has been interpreted as genetic support for "races." A recent study in which >350 microsatellites were studied in a global sample of humans showed that they could be grouped according to their continental origin, and this was widely interpreted as evidence for a discrete distribution of human genetic diversity. Here, we investigate how study design can influence such conclusions. Our results show that when individuals are sampled homogeneously from around the globe, the pattern seen is one of gradients of allele frequencies that extend over the entire world, rather than discrete clusters. Therefore, there is no reason to assume that major genetic discontinuities exist between different continents or "races."
Link
September 25, 2004
Contribution of narrow abilities other than g were previously neglected
According to this new paper, the contribution of narrow cognitive abilities in various tests was obscured by previous research which identified only the general intelligence factor g as having a significant effect. Using a more thorough multidimensional analysis, the authors demonstrate the power of these narrow cognitive abilities. For example, according to the authors:
Intelligence (Article in press)
Differential ability antecedents of general and specific dimensions of declarative knowledge: More than g
Charlie L. Reeve
The purpose of the current study is to test the proposition that the relative contribution of narrow abilities (but not of g) may have been obscured in prior research due to a failure to employ fully multidimensional latent variable analyses. The current study corrects for these deficiencies and examines the relationships between cognitive abilities and domain-specific declarative knowledge. Results show that when observed criterion test scores were individually regressed on abilities, only g was consistently related to the criteria. However, when a latent variable analysis was applied to the same data, both g and narrow ability factors accounted for substantial portions of variance in different latent criterion constructs. Implications are discussed.
Link
the part of quantitative ability that is distinct from g accounted for approximately 65% of the variance in math–science knowledge that is independent of general knowledge for males, and 53% for females. The magnitude of these relations provides clear evidence for the psychological significance of this narrow ability.This research is refreshing, since it shows the fallacy of many g fetishists who have interpreted (wrongly) past lack of evidence for the importance of narrow factors as evidence that they were unimportant. Actually, they are very important, but past methods were unable to discover their significance.
Intelligence (Article in press)
Differential ability antecedents of general and specific dimensions of declarative knowledge: More than g
Charlie L. Reeve
The purpose of the current study is to test the proposition that the relative contribution of narrow abilities (but not of g) may have been obscured in prior research due to a failure to employ fully multidimensional latent variable analyses. The current study corrects for these deficiencies and examines the relationships between cognitive abilities and domain-specific declarative knowledge. Results show that when observed criterion test scores were individually regressed on abilities, only g was consistently related to the criteria. However, when a latent variable analysis was applied to the same data, both g and narrow ability factors accounted for substantial portions of variance in different latent criterion constructs. Implications are discussed.
Link
Better nutrition of less privileged causes generational IQ gains
A new article uses full-distribution data (as opposed to a simple comparison of means) to determine that IQ gains across thirty years (also known as the "Flynn effect") are due to better nutrition of the less privileged classes. There has been no substantial increase at the higher-IQ end of the distribution, unlike the less privileged classes which are "catching up" in terms of IQ.
Interestingly, better nutrition among the less privileged has served to reduce the spread of IQ which has a lower standard deviation in the more recent sample than in the one taken 30 years earlier. We know that the standard deviation of the IQ distribution shows both great variation in different populations and geographical structuring. Therefore, it appears that populations with the same mean IQ may have a different potential for enhancing their IQ via better nutrition in the future.
Intelligence (Article in press)
The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: Supporting evidence for the nutrition hypothesis
Roberto Colom et al.
Generational intelligence gains are one intriguing finding in science. Nutrition and cognitive stimulation are among the most remarkable causes of the upward trend in intelligence. The nutrition hypothesis predicts a primary impact on the most deprived, producing disproportionate gains at low intelligence levels. The cognitive stimulation hypothesis predicts gains along the intelligence distribution. However, data from the entire distribution are rarely available. The present study compares a sample of children tested in 1970 with an equivalent sample tested 30 years later. Data for the entire distributions were available. The results are consistent with the nutrition hypothesis, because the gains were mainly concentrated in the lower and medium halves of the distribution and were negligible in the very top half of the distribution. Moreover, an impressive gradual decrease in the gains was observed from the lower half to the top half of the distribution.
Link
Interestingly, better nutrition among the less privileged has served to reduce the spread of IQ which has a lower standard deviation in the more recent sample than in the one taken 30 years earlier. We know that the standard deviation of the IQ distribution shows both great variation in different populations and geographical structuring. Therefore, it appears that populations with the same mean IQ may have a different potential for enhancing their IQ via better nutrition in the future.
Intelligence (Article in press)
The generational intelligence gains are caused by decreasing variance in the lower half of the distribution: Supporting evidence for the nutrition hypothesis
Roberto Colom et al.
Generational intelligence gains are one intriguing finding in science. Nutrition and cognitive stimulation are among the most remarkable causes of the upward trend in intelligence. The nutrition hypothesis predicts a primary impact on the most deprived, producing disproportionate gains at low intelligence levels. The cognitive stimulation hypothesis predicts gains along the intelligence distribution. However, data from the entire distribution are rarely available. The present study compares a sample of children tested in 1970 with an equivalent sample tested 30 years later. Data for the entire distributions were available. The results are consistent with the nutrition hypothesis, because the gains were mainly concentrated in the lower and medium halves of the distribution and were negligible in the very top half of the distribution. Moreover, an impressive gradual decrease in the gains was observed from the lower half to the top half of the distribution.
Link
September 24, 2004
Taller populations are not more sexually dimorphic in stature
Previously it was thought that taller populations tended to have a greater degree of sexual dimorphism in stature, i.e., that male-female differences in stature were more pronounced in them. A new paper finds that there exists a strong phylogenetic signal in human stature; in other words, human stature variations correspond to some degree with our knowledge of the evolutionary history of modern human populations and the population "splits" which have given rise to modern groups. Moreover, the re-analysis of data from 124 human populations disproves the idea that taller populations are more sexually dimorphic in stature.
Journal of Human Evolution (Article in Press)
Human size evolution: no evolutionary allometric relationship between male and female stature
Anders Gustafsson et al.
In many animal groups, sexual size dimorphism tends to be more pronounced in species with large body size. Similarly, in a previous cross-cultural analysis, male and female stature in humans were shown to be positively allometrically related, indicating a similar relationship where populations with larger stature were more dimorphic. In this study, we re-examine the hypothesis of an allometric relationship between the sexes using phylogenetic methodology. First, however, we tested whether there exist phylogenetic signals in male and female stature. Data on mean stature from 124 human populations was gathered from the literature. A phylogenetic test showed that male and female stature were significantly associated with phylogeny. These results indicate that comparative methods that to some degree incorporate genetic relatedness between populations are crucial when analyzing human size evolution in a cross-cultural context. Further, neither non-phylogenetic nor phylogenetic analyses revealed any allometric relationship between male and female stature. Thus, we found no support for the idea that sexual dimorphism increases with increasing stature in humans.
Link
Journal of Human Evolution (Article in Press)
Human size evolution: no evolutionary allometric relationship between male and female stature
Anders Gustafsson et al.
In many animal groups, sexual size dimorphism tends to be more pronounced in species with large body size. Similarly, in a previous cross-cultural analysis, male and female stature in humans were shown to be positively allometrically related, indicating a similar relationship where populations with larger stature were more dimorphic. In this study, we re-examine the hypothesis of an allometric relationship between the sexes using phylogenetic methodology. First, however, we tested whether there exist phylogenetic signals in male and female stature. Data on mean stature from 124 human populations was gathered from the literature. A phylogenetic test showed that male and female stature were significantly associated with phylogeny. These results indicate that comparative methods that to some degree incorporate genetic relatedness between populations are crucial when analyzing human size evolution in a cross-cultural context. Further, neither non-phylogenetic nor phylogenetic analyses revealed any allometric relationship between male and female stature. Thus, we found no support for the idea that sexual dimorphism increases with increasing stature in humans.
Link
September 23, 2004
Benefits of Mediterranean Diet
A new study from Europe in this morning's Journal of the American Medical Association shows just how powerful the effect of following healthy lifestyle advice can be over the years, reports The Early Show's Dr. Emily Senay.
Researchers looked at people aged 70 to 90 for more than a decade, and found those who adhered to a healthy low-fat Mediterranean-style diet lowered their risk of death by 23 percent. People who drank alcohol moderately lowered their risk by 22 percent. Physical activity lowered the risk by 37 percent. Nonsmoking lowered the death risk by 22 percent. And people who had all four of these healthy lifestyle factors lowered their risk of death from any cause by 65 percent.
It's powerful proof that a healthy lifestyle can work wonders.
The Mediterranean diet comes from countries like Italy and Greece. It's high in foods that provide health benefits like whole grains, fruits, vegetables, legumes, nuts, fish and olive oil.
It also includes low amounts of meat, dairy and saturated fats, and moderate alcohol consumption. Another new study showed that the Mediterranean diet reduced metabolic syndrome, a cluster of symptoms that puts people at a much higher risk for heart disease and Type 2 diabetes later in life like obesity, fat buildup in the arteries, high blood pressure, and glucose or blood sugar intolerance.
People on the Mediterranean diet had significant decreases in metabolic syndrome symptoms and risk factors and improvements in good cholesterol compared to those who weren't on the diet. There was also evidence that the healthier eaters suffered less from the inflammation of cells that may contribute to the risk of disease.
Two additional studies in the journal reinforce the importance of exercise in the health equation, even low-intensity exercise like walking. Physical activity was associated with better mental functioning in older women. Women aged 70 and older who participated in higher levels of physical activity scored better on cognitive performance tests and showed less cognitive decline than women who were less active.
A different study showed that even walking is associated with reduced risk of Alzheimer's in older men. Older men who walked the least had nearly twice the risk for diseases like Alzheimer's, compared to men who walked the most. This is the first time that a low-intensity exercise has been proven to keep the mind sharp.
Link (CBS)
Researchers looked at people aged 70 to 90 for more than a decade, and found those who adhered to a healthy low-fat Mediterranean-style diet lowered their risk of death by 23 percent. People who drank alcohol moderately lowered their risk by 22 percent. Physical activity lowered the risk by 37 percent. Nonsmoking lowered the death risk by 22 percent. And people who had all four of these healthy lifestyle factors lowered their risk of death from any cause by 65 percent.
It's powerful proof that a healthy lifestyle can work wonders.
The Mediterranean diet comes from countries like Italy and Greece. It's high in foods that provide health benefits like whole grains, fruits, vegetables, legumes, nuts, fish and olive oil.
It also includes low amounts of meat, dairy and saturated fats, and moderate alcohol consumption. Another new study showed that the Mediterranean diet reduced metabolic syndrome, a cluster of symptoms that puts people at a much higher risk for heart disease and Type 2 diabetes later in life like obesity, fat buildup in the arteries, high blood pressure, and glucose or blood sugar intolerance.
People on the Mediterranean diet had significant decreases in metabolic syndrome symptoms and risk factors and improvements in good cholesterol compared to those who weren't on the diet. There was also evidence that the healthier eaters suffered less from the inflammation of cells that may contribute to the risk of disease.
Two additional studies in the journal reinforce the importance of exercise in the health equation, even low-intensity exercise like walking. Physical activity was associated with better mental functioning in older women. Women aged 70 and older who participated in higher levels of physical activity scored better on cognitive performance tests and showed less cognitive decline than women who were less active.
A different study showed that even walking is associated with reduced risk of Alzheimer's in older men. Older men who walked the least had nearly twice the risk for diseases like Alzheimer's, compared to men who walked the most. This is the first time that a low-intensity exercise has been proven to keep the mind sharp.
Link (CBS)
September 22, 2004
Dissection of mtDNA Haplogroup H
mtDNA haplogroup H is very widely distributed in Caucasoid populations reaching very high frequencies. This new study suggests that two subhaplogroups H1 and H3 diffused from the Franco-Cantabrian refuge after the Last Glacial Maximum.
Am. J. Hum. Genet., 75:000, 2004
The Molecular Dissection of mtDNA Haplogroup H Confirms That the Franco-Cantabrian Glacial Refuge Was a Major Source for the European Gene Pool
Alessandro Achilli et al.
Complete sequencing of 62 mitochondrial DNAs (mtDNAs) belonging (or very closely related) to haplogroup H revealed that this mtDNA haplogroup—by far the most common in Europe—is subdivided into numerous subhaplogroups, with at least 15 of them (H1–H15) identifiable by characteristic mutations. All the haplogroup H mtDNAs found in 5,743 subjects from 43 populations were then screened for diagnostic markers of subhaplogroups H1 and H3. This survey showed that both subhaplogroups display frequency peaks, centered in Iberia and surrounding areas, with distributions declining toward the northeast and southeast—a pattern extremely similar to that previously reported for mtDNA haplogroup V. Furthermore, the coalescence ages of H1 and H3 (~11,000 years) are close to that previously reported for V. These findings have major implications for the origin of Europeans, since they attest that the Franco-Cantabrian refuge area was indeed the source of late-glacial expansions of hunter-gatherers that repopulated much of Central and Northern Europe from ~15,000 years ago. This has also some implications for disease studies. For instance, the high occurrence of H1 and H3 in Iberia led us to re-evaluate the haplogroup distribution in 50 Spanish families affected by nonsyndromic sensorineural deafness due to the A1555G mutation. The survey revealed that the previously reported excess of H among these families is caused entirely by H3 and is due to a major, probably nonrecent, founder event.
Link
Am. J. Hum. Genet., 75:000, 2004
The Molecular Dissection of mtDNA Haplogroup H Confirms That the Franco-Cantabrian Glacial Refuge Was a Major Source for the European Gene Pool
Alessandro Achilli et al.
Complete sequencing of 62 mitochondrial DNAs (mtDNAs) belonging (or very closely related) to haplogroup H revealed that this mtDNA haplogroup—by far the most common in Europe—is subdivided into numerous subhaplogroups, with at least 15 of them (H1–H15) identifiable by characteristic mutations. All the haplogroup H mtDNAs found in 5,743 subjects from 43 populations were then screened for diagnostic markers of subhaplogroups H1 and H3. This survey showed that both subhaplogroups display frequency peaks, centered in Iberia and surrounding areas, with distributions declining toward the northeast and southeast—a pattern extremely similar to that previously reported for mtDNA haplogroup V. Furthermore, the coalescence ages of H1 and H3 (~11,000 years) are close to that previously reported for V. These findings have major implications for the origin of Europeans, since they attest that the Franco-Cantabrian refuge area was indeed the source of late-glacial expansions of hunter-gatherers that repopulated much of Central and Northern Europe from ~15,000 years ago. This has also some implications for disease studies. For instance, the high occurrence of H1 and H3 in Iberia led us to re-evaluate the haplogroup distribution in 50 Spanish families affected by nonsyndromic sensorineural deafness due to the A1555G mutation. The survey revealed that the previously reported excess of H among these families is caused entirely by H3 and is due to a major, probably nonrecent, founder event.
Link
September 21, 2004
Between-Group Variation is similar for Y-chromosomes and mtDNA
A new study has discovered that the between-group variation variation in human Y-chromosomes and mtDNA is similar (0.334 vs. 0.382). This has three important implications:
Nature Genetics (Published online: 19 September 2004; | doi:10.1038/ng1428)
Global patterns of human mitochondrial DNA and Y-chromosome structure are not influenced by higher migration rates of females versus males
Jason A Wilder et al.
Global-scale patterns of human population structure may be influenced by the rate of migration among populations that is nearly eight times higher for females than for males. This difference is attributed mainly to the widespread practice of patrilocality, in which women move into their mates' residences after marriage1. Here we directly test this hypothesis by comparing global patterns of DNA sequence variation on the Y chromosome and mitochondrial DNA (mtDNA) in the same panel of 389 individuals from ten populations (four from Africa and two each from Europe, Asia and Oceania). We introduce a new strategy to assay Y-chromosome variation that identifies a high density of single-nucleotide polymorphisms, allows complete sequencing of all individuals rather than relying on predetermined markers and provides direct sequence comparisons with mtDNA. We found the overall proportion of between-group variation (Phi ST) to be 0.334 for the Y chromosome and 0.382 for mtDNA. Genetic differentiation between populations was similar for the Y chromosome and mtDNA at all geographic scales that we tested. Although patrilocality may be important at the local scale2, 3, patterns of genetic structure on the continental and global scales are not shaped by the higher rate of migration among females than among males.
Link
- It was previously thought that since women tend to move to their husbands' homes, female genes travelled wider than men's, "homogenizing" the mitochondrial gene pool of mankind. This new research disproves this idea, as human populations are differentiated about the same in their Y-chromosomes and mtDNA.
- The higher female effective population size throughout human prehistory (a widely accepted idea) together with these new results lead to the conclusion that "our observation of roughly equal between-group components of variation for the Y chromosome and mtDNA implies a lower rate of migration for females than for males among the widely spaced populations we surveyed." In other words, men's genes travelled more than women's.
- Previous estimates of Y-chromosome diverstiy used single-nucleotide polymorphisms (SNPs) which were known to vary between populations. As a result, Y-chromosome population differentiation tended to be overemphasized in the past. On the other hand for mtDNA studies used hypervariable portions of the control region where mutation rates are higher than in coding regions (that actually do useful stuff). Therefore, mtDNA population differentiation tended to be underestimated in the past.
Nature Genetics (Published online: 19 September 2004; | doi:10.1038/ng1428)
Global patterns of human mitochondrial DNA and Y-chromosome structure are not influenced by higher migration rates of females versus males
Jason A Wilder et al.
Global-scale patterns of human population structure may be influenced by the rate of migration among populations that is nearly eight times higher for females than for males. This difference is attributed mainly to the widespread practice of patrilocality, in which women move into their mates' residences after marriage1. Here we directly test this hypothesis by comparing global patterns of DNA sequence variation on the Y chromosome and mitochondrial DNA (mtDNA) in the same panel of 389 individuals from ten populations (four from Africa and two each from Europe, Asia and Oceania). We introduce a new strategy to assay Y-chromosome variation that identifies a high density of single-nucleotide polymorphisms, allows complete sequencing of all individuals rather than relying on predetermined markers and provides direct sequence comparisons with mtDNA. We found the overall proportion of between-group variation (Phi ST) to be 0.334 for the Y chromosome and 0.382 for mtDNA. Genetic differentiation between populations was similar for the Y chromosome and mtDNA at all geographic scales that we tested. Although patrilocality may be important at the local scale2, 3, patterns of genetic structure on the continental and global scales are not shaped by the higher rate of migration among females than among males.
Link
September 20, 2004
Demic diffusion of Han Chinese culture
The Han are the most important ethnic group in China. This study shows that while Han Y-chromosomes are relatively homogeneous, with southern Hans having mostly patrilineages of northern origin, in mtDNA the southern Hans are about evenly split between northern and southern matrilineages. The spread of the Han culture and the northern Han people into the south occurred during the last 2,000 years.
Nature 431, 302 - 305 (16 September 2004); doi:10.1038/nature02878
Genetic evideznce supports demic diffusion of Han culture
Bo Wen et al.
The spread of culture and language in human populations is explained by two alternative models: the demic diffusion model, which involves mass movement of people; and the cultural diffusion model, which refers to cultural impact between populations and involves limited genetic exchange between them. The mechanism of the peopling of Europe has long been debated, a key issue being whether the diffusion of agriculture and language from the Near East was concomitant with a large movement of farmers. Here we show, by systematically analysing Y-chromosome and mitochondrial DNA variation in Han populations, that the pattern of the southward expansion of Han culture is consistent with the demic diffusion model, and that males played a larger role than females in this expansion. The Han people, who all share the same culture and language, exceed 1.16 billion (2000 census), and are by far the largest ethnic group in the world. The expansion process of Han culture is thus of great interest to researchers in many fields.
Link
Nature 431, 302 - 305 (16 September 2004); doi:10.1038/nature02878
Genetic evideznce supports demic diffusion of Han culture
Bo Wen et al.
The spread of culture and language in human populations is explained by two alternative models: the demic diffusion model, which involves mass movement of people; and the cultural diffusion model, which refers to cultural impact between populations and involves limited genetic exchange between them. The mechanism of the peopling of Europe has long been debated, a key issue being whether the diffusion of agriculture and language from the Near East was concomitant with a large movement of farmers. Here we show, by systematically analysing Y-chromosome and mitochondrial DNA variation in Han populations, that the pattern of the southward expansion of Han culture is consistent with the demic diffusion model, and that males played a larger role than females in this expansion. The Han people, who all share the same culture and language, exceed 1.16 billion (2000 census), and are by far the largest ethnic group in the world. The expansion process of Han culture is thus of great interest to researchers in many fields.
Link
September 18, 2004
Reconsideration of the Neolithic of Northwestern Europe
This important article deconstructs the ideological excesses of mainly British "post-processual" archaeology.
CURRENT ANTHROPOLOGY Volume 45, Number S4, August-October 2004
How the West Was Lost
A Reconsideration of Agricultural Origins in Britain, Ireland, and Southern Scandinavia
by Peter Rowley-Conwy
Post-processual views of the transition to agriculture in Northwestern Europe have sought to decouple ideology and subsistence economy as a means of protecting the status of ideology as the sole cause of change. Ideology (as reflected in material culture and monument building) changed abruptly. To achieve the required decoupling, subsistence is therefore portrayed as having changed slowly. This implies three things: (1) Mesolithic foragers were gradually intensifying their subsistence economy. (2) Neolithic people subsisted mainly on wild animals and plants and were nomadic. (3) Subsistence change across the ideological transition was slow, continuous, and seamless. Many other scholars, although not post-processualists, have come to accept these three points. But as the post-processual view has become the consensus, the data from Britain, Ireland, and southern Scandinavia have all been leading in the opposite direction: (1) There is no reason to think that Mesolithic foragers were intensifying economically. (2) Neolithic people subsisted mainly on cultivated plants and domestic animals and were fully sedentary. (3) The transition to agriculture was rapid and probably traumatic. The current consensus has yet to incorporate these data into its explanatory framework.
Link
CURRENT ANTHROPOLOGY Volume 45, Number S4, August-October 2004
How the West Was Lost
A Reconsideration of Agricultural Origins in Britain, Ireland, and Southern Scandinavia
by Peter Rowley-Conwy
Post-processual views of the transition to agriculture in Northwestern Europe have sought to decouple ideology and subsistence economy as a means of protecting the status of ideology as the sole cause of change. Ideology (as reflected in material culture and monument building) changed abruptly. To achieve the required decoupling, subsistence is therefore portrayed as having changed slowly. This implies three things: (1) Mesolithic foragers were gradually intensifying their subsistence economy. (2) Neolithic people subsisted mainly on wild animals and plants and were nomadic. (3) Subsistence change across the ideological transition was slow, continuous, and seamless. Many other scholars, although not post-processualists, have come to accept these three points. But as the post-processual view has become the consensus, the data from Britain, Ireland, and southern Scandinavia have all been leading in the opposite direction: (1) There is no reason to think that Mesolithic foragers were intensifying economically. (2) Neolithic people subsisted mainly on cultivated plants and domestic animals and were fully sedentary. (3) The transition to agriculture was rapid and probably traumatic. The current consensus has yet to incorporate these data into its explanatory framework.
Link
Craniometric study on Neolithic dispersals
CURRENT ANTHROPOLOGY Volume 45, Number S4, August-October 2004
A Regional Biological Approach to the Spread of Farming in Europe Anatolia, the Levant, South-Eastern Europe, and the Mediterranean
by Ron Pinhasi and Mark Pluciennik
This article examines the potential contribution of archaeological human skeletal material, in particular craniometric data, to interpretations of the nature of the transition to farming in Europe. The material is discussed particularly in relation to recent debates about demographic variables and processes and modern genetic frequency patterns. It is suggested that biological morphometrics enables the comparison of ancient populations on a regional basis. Analysis of the material suggests that there was considerable morphological heterogeneity among the earliest farmers of the Levant belonging to the Pre-Pottery Neolithic but that similar variability is generally not seen among the earliest mainland agriculturalists of south-eastern Europe. We propose that this may be explained by the existence of a genetic "bottleneck" among Anatolian populations and that it supports models of the largely exogenous origin of many early Neolithic populations in this region. Regional comparisons further demonstrate a biologically more complex relationship between Mesolithic and Neolithic populations in the central and western Mediterranean. The regional and chronological variability of transitions to farming is stressed, and it is pointed out that different techniques highlight different aspects of the processes involved at a range of scales and resolutions.
Link
A Regional Biological Approach to the Spread of Farming in Europe Anatolia, the Levant, South-Eastern Europe, and the Mediterranean
by Ron Pinhasi and Mark Pluciennik
This article examines the potential contribution of archaeological human skeletal material, in particular craniometric data, to interpretations of the nature of the transition to farming in Europe. The material is discussed particularly in relation to recent debates about demographic variables and processes and modern genetic frequency patterns. It is suggested that biological morphometrics enables the comparison of ancient populations on a regional basis. Analysis of the material suggests that there was considerable morphological heterogeneity among the earliest farmers of the Levant belonging to the Pre-Pottery Neolithic but that similar variability is generally not seen among the earliest mainland agriculturalists of south-eastern Europe. We propose that this may be explained by the existence of a genetic "bottleneck" among Anatolian populations and that it supports models of the largely exogenous origin of many early Neolithic populations in this region. Regional comparisons further demonstrate a biologically more complex relationship between Mesolithic and Neolithic populations in the central and western Mediterranean. The regional and chronological variability of transitions to farming is stressed, and it is pointed out that different techniques highlight different aspects of the processes involved at a range of scales and resolutions.
Link
The African mtDNA landscape
In the comments of a previous post, I mentioned that the present-day populations of East Africa are only partially descended from the prehistoric East Africans which gave rise to all non-African groups. Apart from the physical anthropological evidence for a lack of craniometric continuity in the region, we also have the findings of population genetics.
Most non-African mtDNA belongs to two macro-groups, called N (frequent in West Eurasians) and M (frequent in East and South Asians and Americans). Both M and N are derived from a particular African group called L3. Thus, it appears that non-Africans are descended from a prehistoric African population which had L3-type mtDNA.
A comprehensive study [1] has studied the distribution of mtDNA haplogroups in present-day African populations:
As we can see, modern East Africans have less than 50% of L3-group mtDNA, with the remainder being either M1 (whose origin is disputed, with some considering it Asian and others African in origin), a little bit of U6 (which is of North African origin), and the remainder (~50%) belongs to L-groups other than L3.
It is clear that this latter component was not present in the East African source of non-African populations in the past. If it were, then it would be present outside Africa. But, even in the Near East, African-specific mtDNA are a minority, mostly confined to Arab populations and attributed to the slave trade [2].
Thus, it appears that a large fraction of present-day East African mitochondrial ancestry is derived from different populations than the ones that spawned non-Africans. This element is probably responsible for the introduction of the Negroid type in the region, which now forms a major element in the population, together with the pre-Negroid East Africans and more recent Caucasoid arrivals from across the Red Sea.
[1] Am. J. Hum. Genet., 71:1082-1111, 2002
[2] Am. J. Hum. Genet., 72:1058-1064, 2003
Most non-African mtDNA belongs to two macro-groups, called N (frequent in West Eurasians) and M (frequent in East and South Asians and Americans). Both M and N are derived from a particular African group called L3. Thus, it appears that non-Africans are descended from a prehistoric African population which had L3-type mtDNA.
A comprehensive study [1] has studied the distribution of mtDNA haplogroups in present-day African populations:
As we can see, modern East Africans have less than 50% of L3-group mtDNA, with the remainder being either M1 (whose origin is disputed, with some considering it Asian and others African in origin), a little bit of U6 (which is of North African origin), and the remainder (~50%) belongs to L-groups other than L3.
It is clear that this latter component was not present in the East African source of non-African populations in the past. If it were, then it would be present outside Africa. But, even in the Near East, African-specific mtDNA are a minority, mostly confined to Arab populations and attributed to the slave trade [2].
Thus, it appears that a large fraction of present-day East African mitochondrial ancestry is derived from different populations than the ones that spawned non-Africans. This element is probably responsible for the introduction of the Negroid type in the region, which now forms a major element in the population, together with the pre-Negroid East Africans and more recent Caucasoid arrivals from across the Red Sea.
[1] Am. J. Hum. Genet., 71:1082-1111, 2002
[2] Am. J. Hum. Genet., 72:1058-1064, 2003
September 17, 2004
Anthropological complexes of European Russia, Baltic States, Belarus and Ukraine
An interesting excerpt translated into English together with a descriptive map. Some terminology of N. N. Cheboksarov regarding the Europeoid race is used in this article which might not be familiar to most people, so I list it here as a reference, text copied from an online source.
II. Europeoid (Eurasian) Great Race:
1. South European (Indo-Mediterranean) Race:
(i) South Indian (Dravidian). ------- "C"
(ii) Anterior Asian
(iii) Mediterranean-Balkan
(iv) Atlanto-Black Sea. ------- "C"
(v) East European --------"C"
2. North European (Atlanto-Baltic) Race:
(i) Atlanto-Baltic
(ii) White Sea-Baltic
"C" -------- contact or transitional group
II. Europeoid (Eurasian) Great Race:
1. South European (Indo-Mediterranean) Race:
(i) South Indian (Dravidian). ------- "C"
(ii) Anterior Asian
(iii) Mediterranean-Balkan
(iv) Atlanto-Black Sea. ------- "C"
(v) East European --------"C"
2. North European (Atlanto-Baltic) Race:
(i) Atlanto-Baltic
(ii) White Sea-Baltic
"C" -------- contact or transitional group
North Europeans take more sickies
Workers in northern Europe are more likely than their southern counterparts to take sick leave, a study has found.
Rates of absenteeism vary hugely around Europe
Staff in Germany, the Netherlands and Finland take the most time off in Europe, a report in the Occupational and Environmental Medicine journal said
Workers in Ireland, Greece and Portugal take the least time off for illness, the study found.
On average, 14.5% of European workers took at least one day off in 2000, the year covered by the study.
Greece had the lowest rate of absenteeism at 6.7% and Finland the highest at 24%.
"This study provides the first scientifically valid description of sickness absence across EU countries," said Dr David Gimeno of the University of Texas School of Public Health in Houston.
The survey looked at absenteeism and ill health in 2000 in the then 15 members of the European Union (EU).
The EU has expanded to 25 members since the survey was carried out.
High cost of 'duvet days'
Sick leave - real and feigned - currently costs UK businesses an estimated £11bn a year.
It is widely perceived to be higher in the public sector than in the private sector, though there is evidence to suggest that absenteeism in large private sector companies matches that in the public sector.
Research carried out by the Confederation of British Industry (CBI) indicates that small firms, where an employee calling in sick often has to talk to the owner, suffer far less absence than large firms.
Link (BBC)September 14, 2004
Inferring Human History: Clues from Y-chromosome haplotypes
It's easy to get lost in the technical jargon of many genetics papers, but this excellent review (pdf) by P.A. Underhill is a great primer on human Y chromosome phylogeny.
September 13, 2004
Move + New Article
After a few years hosted at geocities, I have finally moved, re-named and reorganized the "Greek Anthropology and Racial Identity" site. The new Anthropological Research Page is now available, and to coincide with its launch, I have put online a new short article on Model-Based Clustering of World Craniometric Variation. I've been playing with Howells' data for several months now, but I've finally decided to scrap the plans for a joint analysis of both his "recent" and "prehistoric" populations for some time in the future. For the time being, readers can read how a large collection of unlabelled crania from recent human populations assort themselves to racial clusters, and hopefully the analysis of the "prehistoric" material will also be added soon.
September 10, 2004
Racial Affinities of Prehistoric East Africans
Afrocentrists and Nordicists alike tend to assert that early East Africans were "Negroid". Since East Africa was the source of multiple migrations of early humans out of Africa, this allows the former to assert a "Negroid" stage in the evolution of Eurasians, or to postulate a later (mythological) stage of "Negroid" East African culture-bearers. Nordicists of the other hand, dissatisfied with the paucity to non-existence of genuine Sub-Saharan African genetic markers in Southeastern Europe have insinuated that Y-haplogroup E3b which originated in East Africa 26ky ago is "Negroid" or that mtDNA haplogroup M1 which according to some also originated in East Africa in Paleolithic times is also "Negroid".
W.W. Howells' study of world craniometric variation is especially relevant to the racial affinity of East Africans before the expansion of Negroids into the region. Howells studied some 2,500+ skulls from 28 populations of recent Homo sapiens based on 57 metric variables [1], including skulls from the Teita tribe of East Africa. These recent Teita tribesmen (and women) clustered with other Sub-Saharan Africans, indicating that (as is obvious) recent Kenyans belong primarily to the Negroid race.
Howells then studied prehistoric East Africans and other humans from around the world to determine whether or not they show any affinities with living races [2]. He did this to examine whether the morphological complexes of modern races can be discerned in remote times. Using the same multivariate approach he studied the Elmenteita, Nakuru and Willey's Kopje skulls from Kenya. His conclusion was that there is no racial continuity between recent Negroid East African skulls and these prehistoric remains, as the following passage illustrates ([2, p. 41]:
[1] Howells WW (1989) Skull shapes and the map: craniometric analyses in the dispersion of modern Homo. Peabody Museum Papers 79:1-189.
[2] Howells WW (1995) Who's Who in skulls: ethnic identification of crania from measurements. Peabody Museum Papers 82:1-108.
W.W. Howells' study of world craniometric variation is especially relevant to the racial affinity of East Africans before the expansion of Negroids into the region. Howells studied some 2,500+ skulls from 28 populations of recent Homo sapiens based on 57 metric variables [1], including skulls from the Teita tribe of East Africa. These recent Teita tribesmen (and women) clustered with other Sub-Saharan Africans, indicating that (as is obvious) recent Kenyans belong primarily to the Negroid race.
Howells then studied prehistoric East Africans and other humans from around the world to determine whether or not they show any affinities with living races [2]. He did this to examine whether the morphological complexes of modern races can be discerned in remote times. Using the same multivariate approach he studied the Elmenteita, Nakuru and Willey's Kopje skulls from Kenya. His conclusion was that there is no racial continuity between recent Negroid East African skulls and these prehistoric remains, as the following passage illustrates ([2, p. 41]:
(...) The DISPOP [Dienekes: DISPOP is Howells' program] results here are not indicative of anything, except a general non-African nature for all these skulls. Display of POPKIN distances (infra) reinforces this and seems to find nearer neighbors among such more generalized populations as Peru, Guam, or Ainu, but also Europeans or even Easter Island.
Remembering that the Teita series (Bantu speakers of southeastern Kenya), and the recent East African skulls in table 4 above, do clearly exhibit African affiliations, it is fair to say, contra Rightmire, that there seems to be no clear continuity here in late prehistory. On the broad scale, looking at an "Out-of-Africa" scenario, one would expect that, in some region between southern and northeastern Africa, some differentiation would have been taking place within a Homo sapiens stock, evolving into something beginning to approximate later Sub-Saharan peoples on the one hand, and evolving in another direction on the other hand. East Africa would be a likely locale for appearance of the latter. So anyone is welcome to argue that this is what Elmenteita et al. are manifesting. The ensuing picture for East Africa, that is to say, would later have beeen changed through replacement by the expansion of Bantu or other "Negroid" tribes.
[1] Howells WW (1989) Skull shapes and the map: craniometric analyses in the dispersion of modern Homo. Peabody Museum Papers 79:1-189.
[2] Howells WW (1995) Who's Who in skulls: ethnic identification of crania from measurements. Peabody Museum Papers 82:1-108.
September 09, 2004
Positive Selection on MMP3 in Europe
Current Biology 14(7), 7 September 2004, Pages 1531-1539
Positive Selection on MMP3 Regulation Has Shaped Heart Disease Risk
Matthew V. Rockman et al.
Abstract
Background: The evolutionary forces of mutation, natural selection, and genetic drift shape the pattern of phenotypic variation in nature, but the roles of these forces in defining the distributions of particular traits have been hard to disentangle. To better understand the mechanisms contributing to common variation in humans, we investigated the evolutionary history of a functional polymorphism in the upstream regulatory region of the MMP3 gene. This single base pair insertion/deletion variant, which results in a run of either 5 or 6 thymidines 1608 bp from the transcription start site, alters transcription factor binding and influences levels of MMP3 mRNA and protein. The polymorphism contributes to variation in arterial traits and to the risk of coronary heart disease and its progression.
Results: Phylogenetic and population genetic analysis of primate sequences indicate that the binding site region is rapidly evolving and has been a hot spot for mutation for tens of millions of years. We also find evidence for the action of positive selection, beginning approximately 24,000 years ago, increasing the frequency of the high-expression allele in Europe but not elsewhere. Positive selection is evident in statistical tests of differentiation among populations and haplotype diversity within populations. Europeans have greater arterial elasticity and suffer dramatically fewer coronary heart disease events than they would have had this selection not occurred.
Conclusions: Locally elevated mutation rates and strong positive selection on a cis-regulatory variant have shaped contemporary phenotypic variation and public health.
Link
Positive Selection on MMP3 Regulation Has Shaped Heart Disease Risk
Matthew V. Rockman et al.
Abstract
Background: The evolutionary forces of mutation, natural selection, and genetic drift shape the pattern of phenotypic variation in nature, but the roles of these forces in defining the distributions of particular traits have been hard to disentangle. To better understand the mechanisms contributing to common variation in humans, we investigated the evolutionary history of a functional polymorphism in the upstream regulatory region of the MMP3 gene. This single base pair insertion/deletion variant, which results in a run of either 5 or 6 thymidines 1608 bp from the transcription start site, alters transcription factor binding and influences levels of MMP3 mRNA and protein. The polymorphism contributes to variation in arterial traits and to the risk of coronary heart disease and its progression.
Results: Phylogenetic and population genetic analysis of primate sequences indicate that the binding site region is rapidly evolving and has been a hot spot for mutation for tens of millions of years. We also find evidence for the action of positive selection, beginning approximately 24,000 years ago, increasing the frequency of the high-expression allele in Europe but not elsewhere. Positive selection is evident in statistical tests of differentiation among populations and haplotype diversity within populations. Europeans have greater arterial elasticity and suffer dramatically fewer coronary heart disease events than they would have had this selection not occurred.
Conclusions: Locally elevated mutation rates and strong positive selection on a cis-regulatory variant have shaped contemporary phenotypic variation and public health.
Link
mtDNA in Iran and India
This article is a great survey of South and Southwest Asian mitochondrial diversity, showing a sharp difference between India and Iran, with the former having a high occurrence of "Proto-Asian" mtDNA types whose frequence falls drastically in Iran.
Indians have traditionally been characterized as being part of the periphery of the Caucasoid race. The subequatorial racial element which distinguishes Indians from Caucasoids-proper has been named Veddoid, Australoid or Palaeo-Indid by various researchers. These new genetic studies have shown Indians to be of mainly dual origins, with West Eurasian racial elements being added to a native South Asian base which persists more strongly in non-caste and southern populations of the subcontinent, and manifests itself primarily in Indian matrilineages.
BMC Genet. 2004 Aug 31;5(1):26.
Most of the extant mtDNA boundaries in South and Southwest Asia were likely shaped during the initial settlement of Eurasia by anatomically modern humans
Metspalu et al.
BACKGROUND: Recent advances in the understanding of the maternal and paternal heritage of south and southwest Asian populations have highlighted their role in the colonization of Eurasia by anatomically modern humans. Further understanding requires a deeper insight into the topology of the branches of the Indian mtDNA phylogenetic tree, which should be contextualized within the phylogeography of the neighboring regional mtDNA variation. Accordingly, we have analyzed mtDNA control and coding region variation in 796 Indian (including both tribal and caste populations from different parts of India) and 436 Iranian mtDNAs. The results were integrated and analyzed together with published data from South, Southeast Asia and West Eurasia. RESULTS: Four new Indian-specific haplogroup M sub-clades were defined. These, in combination with two previously described haplogroups, encompass approximately one third of the haplogroup M mtDNAs in India. Their phylogeography and spread among different linguistic phyla and social strata was investigated in detail. Furthermore, the analysis of the Iranian mtDNA pool revealed patterns of limited reciprocal gene flow between Iran and the Indian sub-continent and allowed the identification of different assemblies of shared mtDNA sub-clades. CONCLUSIONS: Since the initial peopling of South and West Asia by anatomically modern humans, when this region may well have provided the initial settlers who colonized much of the rest of Eurasia, the gene flow in and out of India of the maternally transmitted mtDNA has been surprisingly limited. Specifically, our analysis of the mtDNA haplogroups, which are shared between Indian and Iranian populations and exhibit coalescence ages corresponding to around the early Upper Paleolithic, indicates that they are present in India largely as Indian-specific sub-lineages. In contrast, other ancient Indian-specific variants of M and R are very rare outside the sub-continent.
Link
Indians have traditionally been characterized as being part of the periphery of the Caucasoid race. The subequatorial racial element which distinguishes Indians from Caucasoids-proper has been named Veddoid, Australoid or Palaeo-Indid by various researchers. These new genetic studies have shown Indians to be of mainly dual origins, with West Eurasian racial elements being added to a native South Asian base which persists more strongly in non-caste and southern populations of the subcontinent, and manifests itself primarily in Indian matrilineages.
BMC Genet. 2004 Aug 31;5(1):26.
Most of the extant mtDNA boundaries in South and Southwest Asia were likely shaped during the initial settlement of Eurasia by anatomically modern humans
Metspalu et al.
BACKGROUND: Recent advances in the understanding of the maternal and paternal heritage of south and southwest Asian populations have highlighted their role in the colonization of Eurasia by anatomically modern humans. Further understanding requires a deeper insight into the topology of the branches of the Indian mtDNA phylogenetic tree, which should be contextualized within the phylogeography of the neighboring regional mtDNA variation. Accordingly, we have analyzed mtDNA control and coding region variation in 796 Indian (including both tribal and caste populations from different parts of India) and 436 Iranian mtDNAs. The results were integrated and analyzed together with published data from South, Southeast Asia and West Eurasia. RESULTS: Four new Indian-specific haplogroup M sub-clades were defined. These, in combination with two previously described haplogroups, encompass approximately one third of the haplogroup M mtDNAs in India. Their phylogeography and spread among different linguistic phyla and social strata was investigated in detail. Furthermore, the analysis of the Iranian mtDNA pool revealed patterns of limited reciprocal gene flow between Iran and the Indian sub-continent and allowed the identification of different assemblies of shared mtDNA sub-clades. CONCLUSIONS: Since the initial peopling of South and West Asia by anatomically modern humans, when this region may well have provided the initial settlers who colonized much of the rest of Eurasia, the gene flow in and out of India of the maternally transmitted mtDNA has been surprisingly limited. Specifically, our analysis of the mtDNA haplogroups, which are shared between Indian and Iranian populations and exhibit coalescence ages corresponding to around the early Upper Paleolithic, indicates that they are present in India largely as Indian-specific sub-lineages. In contrast, other ancient Indian-specific variants of M and R are very rare outside the sub-continent.
Link
Importance of sexual selection in recent human evolution
See also the entry on Higher female effective population size in recent human evolution
Evolution Int J Org Evolution. 2004 Jul;58(7):1613-6.
Estimating the strength of sexual selection from Y-chromosome and mitochondrial DNA diversity.
Wade MJ et al.
We show that a sex difference in the opportunity for selection results in sex differences in the strength of random genetic drift and thus creates different patterns of genetic diversity for maternally and paternally inherited haploid genes. We derive the effective population size Ne for a male-limited or female-limited haploid gene in terms of I, the "opportunity for selection" or the variance in relative fitness. Because the variance in relative fitness of males can be an order of magnitude larger than that of females, the Ne is much smaller for males than it is for females. We derive both nonequilibrium and equilibrium expressions for F(ST) in terms of I and show how the portion of I owing to sexual selection, Imates, that is, the variation among males in mate numbers, is a simple function of the F's for cytoplasmic (female inherited) and Y-linked (male inherited) genes. Because multiple, transgenerational data are lacking to apply the nonequilibrium expression, we apply only the equilibrium model to published data on Y chromosome and mitochondrial sequence divergence in Homo sapiens to quantify the opportunity for sexual selection. The estimate suggests that sexual selection in humans represents a minimum of 54.8% of total selection, supporting Darwin's proposal that sexual selection has played a significant role in human evolution and the recent proposal regarding a shift from polygamy to monogamy in humans.
Link
Evolution Int J Org Evolution. 2004 Jul;58(7):1613-6.
Estimating the strength of sexual selection from Y-chromosome and mitochondrial DNA diversity.
Wade MJ et al.
We show that a sex difference in the opportunity for selection results in sex differences in the strength of random genetic drift and thus creates different patterns of genetic diversity for maternally and paternally inherited haploid genes. We derive the effective population size Ne for a male-limited or female-limited haploid gene in terms of I, the "opportunity for selection" or the variance in relative fitness. Because the variance in relative fitness of males can be an order of magnitude larger than that of females, the Ne is much smaller for males than it is for females. We derive both nonequilibrium and equilibrium expressions for F(ST) in terms of I and show how the portion of I owing to sexual selection, Imates, that is, the variation among males in mate numbers, is a simple function of the F's for cytoplasmic (female inherited) and Y-linked (male inherited) genes. Because multiple, transgenerational data are lacking to apply the nonequilibrium expression, we apply only the equilibrium model to published data on Y chromosome and mitochondrial sequence divergence in Homo sapiens to quantify the opportunity for sexual selection. The estimate suggests that sexual selection in humans represents a minimum of 54.8% of total selection, supporting Darwin's proposal that sexual selection has played a significant role in human evolution and the recent proposal regarding a shift from polygamy to monogamy in humans.
Link
September 07, 2004
Romany Gypsies came out of India
Monday, 6 September 2004
Anna Salleh
ABC Science Online
The research, by Professor Luba Kalaydjieva of the University of Western Australia and team, looked at the origins of eight to 10 million people in Europe commonly known as Gypsies.
Roma, Romani or Romany are other names for this community, which has featured in movies such as Latcho Drom.
"[The research] is the best evidence yet of the Indian origins of the Gypsies," the researchers write in an article published online ahead of print in the American Journal of Human Genetics.
Complete Story
Anna Salleh
ABC Science Online
The research, by Professor Luba Kalaydjieva of the University of Western Australia and team, looked at the origins of eight to 10 million people in Europe commonly known as Gypsies.
Roma, Romani or Romany are other names for this community, which has featured in movies such as Latcho Drom.
"[The research] is the best evidence yet of the Indian origins of the Gypsies," the researchers write in an article published online ahead of print in the American Journal of Human Genetics.
Complete Story
Did the First Americans Come From, Er, Australia?
(Top Stories - Reuters)
EXETER, England (Reuters) - Anthropologists stepped into a hornets' nest on Monday, revealing research that suggests the original inhabitants of America may in fact have come from what is now known as Australia.
The claim will be extremely unwelcome to today's native Americans who came overland from Siberia and say they were there first.
But Silvia Gonzalez from John Moores University in Liverpool said skeletal evidence pointed strongly to this unpalatable truth and hinted that recovered DNA would corroborate it.
"This is very contentious," Gonzalez, a Mexican, said with a smile at the annual meeting of the British association for the Advancement of Science. "They (native Americans) cannot claim to have been the first people there."
She said there was very strong evidence that the first migration came from Australia via Japan and Polynesia and down the Pacific Coast of America.
Skulls of a people with distinctively long and narrow heads discovered in Mexico and California predated by several thousand years the more rounded features of the skulls of native Americans.
One particularly well preserved skull of a long-face woman had been carbon dated to 12,700 years ago, whereas the oldest accurately dated native American skull was only about 9,000 years old.
"We have extracted her DNA. It is going to be a bomb," she said, declining to give details but adding that the tests carried out so far were being replicated to make sure they were accurate.
She said there were tales from Spanish missionaries of an isolated coastal community of long-face people in Baja California of a completely different race and rituals from other communities in America at the time.
These last survivors were wiped out by diseases imported by the Spanish conquerors, Gonzalez said.
The research is one of 11 different projects in America, Africa, Asia and the Middle East being funded over a four-year period by Britain's Natural Environment Research Council.
The projects, focusing on diet, dating and dispersal of people down the millennia in the face of climate change, aim to rewrite anthropology.
"We want to make headlines from heads," said Professor Clive Gamble of Southampton university. "DNA will give us a completely new map of the world and how we peopled it."
Link
EXETER, England (Reuters) - Anthropologists stepped into a hornets' nest on Monday, revealing research that suggests the original inhabitants of America may in fact have come from what is now known as Australia.
The claim will be extremely unwelcome to today's native Americans who came overland from Siberia and say they were there first.
But Silvia Gonzalez from John Moores University in Liverpool said skeletal evidence pointed strongly to this unpalatable truth and hinted that recovered DNA would corroborate it.
"This is very contentious," Gonzalez, a Mexican, said with a smile at the annual meeting of the British association for the Advancement of Science. "They (native Americans) cannot claim to have been the first people there."
She said there was very strong evidence that the first migration came from Australia via Japan and Polynesia and down the Pacific Coast of America.
Skulls of a people with distinctively long and narrow heads discovered in Mexico and California predated by several thousand years the more rounded features of the skulls of native Americans.
One particularly well preserved skull of a long-face woman had been carbon dated to 12,700 years ago, whereas the oldest accurately dated native American skull was only about 9,000 years old.
"We have extracted her DNA. It is going to be a bomb," she said, declining to give details but adding that the tests carried out so far were being replicated to make sure they were accurate.
She said there were tales from Spanish missionaries of an isolated coastal community of long-face people in Baja California of a completely different race and rituals from other communities in America at the time.
These last survivors were wiped out by diseases imported by the Spanish conquerors, Gonzalez said.
The research is one of 11 different projects in America, Africa, Asia and the Middle East being funded over a four-year period by Britain's Natural Environment Research Council.
The projects, focusing on diet, dating and dispersal of people down the millennia in the face of climate change, aim to rewrite anthropology.
"We want to make headlines from heads," said Professor Clive Gamble of Southampton university. "DNA will give us a completely new map of the world and how we peopled it."
Link
September 06, 2004
Γενετική των Ελλήνων
Μιας και η ενημέρωση για θέματα πληθυσμιακής γενετικής στο διαδίκτυο στην Ελληνική γλώσσα είναι σχεδόν ανύπαρκτη, αποφάσισα να ξεκινήσω ένα καινούριο αρχείο για την παρουσίαση τέτοιων θεμάτων στην Ελληνική γλώσσα. Η Γενετική των Ελλήνων ξεκίνησε με μια εκτενή δημοσίευση σχετικά με τα Χρωματοσώματα Υ των Ελλήνων. Όπως αναφέρω και στην Ταυτότητα του Ιστότοπου ελπίζω να προστεθούν και άλλοι συγγραφείς με γνώσεις γενετικής στην καινούρια αυτή προσπάθεια.
September 04, 2004
Non-Caucasoid Admixture in Austria and Germany
According to [1] the following non-Caucasoid Y-chromosomes were found in a sample from Muenster, Germany and Innsbruck, Austria.
Austria: 1/129 E*(xE3b) (Sub-Saharan African). Total admixture: 0.8%
Germany: 1/95 A* (Sub-Saharan African), 2 BCD (African or Asian). Total admixture: 3.2%
[1] María Brion et al., A collaborative study of the EDNAP group regarding Y-chromosome binary polymorphism analysis, Forensic Science International, In Press, Corrected Proof, Available online 21 August 2004
Austria: 1/129 E*(xE3b) (Sub-Saharan African). Total admixture: 0.8%
Germany: 1/95 A* (Sub-Saharan African), 2 BCD (African or Asian). Total admixture: 3.2%
[1] María Brion et al., A collaborative study of the EDNAP group regarding Y-chromosome binary polymorphism analysis, Forensic Science International, In Press, Corrected Proof, Available online 21 August 2004
September 01, 2004
mtDNA and the western Bantu expansion
Human Genetics (Online First)
DOI: 10.1007/s00439-004-1164-0
Insights into the western Bantu dispersal: mtDNA lineage analysis in Angola
Stéphanie Plaza et al.
Abstract
Africa is the homeland of humankind and it is known to harbour the highest levels of human genetic diversity. However, many continental regions, especially in the sub-Saharan side, still remain largely uncharacterized (i.e. southwest and central Africa). Here, we examine the mitochondrial DNA (mtDNA) variation in a sample from Angola. The two mtDNA hypervariable segments as well as the 9-bp tandem repeat on the COII/tRNAlys intergenic region have allowed us to allocate mtDNAs to common African haplogroups. Angola lies in the southern end of the putative western branch of the Bantu expansion, where it met the local Khoisan populations. Angolan mtDNA lineages show basically a Bantu substrate with no traces of Khoisan lineages. Roughly, more than half of the southwestern mtDNA pool can be assigned to west Africa, ~25% to central Africa and a significant 16% to east Africa, which points to the western gene pool having contributed most to the mtDNA lineages in Angola. We have also detected signals of extensive gene flow from southeast Africa. Our results suggest that eastern and western Bantu expansion routes were not independent from each other, and were connected south of the rainforest and along the southern African savannah. In agreement with historical documentation, the analysis also showed that the Angola mtDNA genetic pool shows affinities with the African lineages from Brazil, the main American destination of the slaves from Angola, although not all lineages in Brazil can be accounted for by the Angolan mtDNA pool.
Link
DOI: 10.1007/s00439-004-1164-0
Insights into the western Bantu dispersal: mtDNA lineage analysis in Angola
Stéphanie Plaza et al.
Abstract
Africa is the homeland of humankind and it is known to harbour the highest levels of human genetic diversity. However, many continental regions, especially in the sub-Saharan side, still remain largely uncharacterized (i.e. southwest and central Africa). Here, we examine the mitochondrial DNA (mtDNA) variation in a sample from Angola. The two mtDNA hypervariable segments as well as the 9-bp tandem repeat on the COII/tRNAlys intergenic region have allowed us to allocate mtDNAs to common African haplogroups. Angola lies in the southern end of the putative western branch of the Bantu expansion, where it met the local Khoisan populations. Angolan mtDNA lineages show basically a Bantu substrate with no traces of Khoisan lineages. Roughly, more than half of the southwestern mtDNA pool can be assigned to west Africa, ~25% to central Africa and a significant 16% to east Africa, which points to the western gene pool having contributed most to the mtDNA lineages in Angola. We have also detected signals of extensive gene flow from southeast Africa. Our results suggest that eastern and western Bantu expansion routes were not independent from each other, and were connected south of the rainforest and along the southern African savannah. In agreement with historical documentation, the analysis also showed that the Angola mtDNA genetic pool shows affinities with the African lineages from Brazil, the main American destination of the slaves from Angola, although not all lineages in Brazil can be accounted for by the Angolan mtDNA pool.
Link
Lithuanian Y-chromosomes and mtDNA
Annals of Human Genetics (OnlineEarly)
doi:10.1046/j.1529-8817.2003.00119.x
Y Chromosome and Mitochondrial DNA Variation in Lithuanians
D. Kasperaviit et al.
Summary
The genetic composition of the Lithuanian population was investigated by analysing mitochondrial DNA hypervariable region 1, RFLP polymorphisms and Y chromosomal biallelic and STR markers in six ethnolinguistic groups of Lithuanians, to address questions about the origin and genetic structure of the present day population. There were no significant genetic differences among ethnolinguistic groups, and an analysis of molecular variance confirmed the homogeneity of the Lithuanian population. MtDNA diversity revealed that Lithuanians are close to both Slavic (Indo-European) and Finno-Ugric speaking populations of Northern and Eastern Europe. Y-chromosome SNP haplogroup analysis showed Lithuanians to be closest to Latvians and Estonians. Significant differences between Lithuanian and Estonian Y chromosome STR haplotypes suggested that these populations have had different demographic histories. We suggest that the observed pattern of Y chromosome diversity in Lithuanians may be explained by a population bottleneck associated with Indo-European contact. Different Y chromosome STR distributions in Lithuanians and Estonians might be explained by different origins or, alternatively, be the result of some period of isolation and genetic drift after the population split.
Link
doi:10.1046/j.1529-8817.2003.00119.x
Y Chromosome and Mitochondrial DNA Variation in Lithuanians
D. Kasperaviit et al.
Summary
The genetic composition of the Lithuanian population was investigated by analysing mitochondrial DNA hypervariable region 1, RFLP polymorphisms and Y chromosomal biallelic and STR markers in six ethnolinguistic groups of Lithuanians, to address questions about the origin and genetic structure of the present day population. There were no significant genetic differences among ethnolinguistic groups, and an analysis of molecular variance confirmed the homogeneity of the Lithuanian population. MtDNA diversity revealed that Lithuanians are close to both Slavic (Indo-European) and Finno-Ugric speaking populations of Northern and Eastern Europe. Y-chromosome SNP haplogroup analysis showed Lithuanians to be closest to Latvians and Estonians. Significant differences between Lithuanian and Estonian Y chromosome STR haplotypes suggested that these populations have had different demographic histories. We suggest that the observed pattern of Y chromosome diversity in Lithuanians may be explained by a population bottleneck associated with Indo-European contact. Different Y chromosome STR distributions in Lithuanians and Estonians might be explained by different origins or, alternatively, be the result of some period of isolation and genetic drift after the population split.
Link
Origin of Canary Islanders
Annals of Human Genetics (OnlineEarly)
doi:10.1046/j.1529-8817.2003.00125.x
A Tale of Aborigines, Conquerors and Slaves: Alu Insertion Polymorphisms and the Peopling of Canary Islands
N. Maca-Meyer et al.
Summary
Classical, mitochondrial DNA (mtDNA) and Y chromosome markers have been used to examine the genetic admixture in present day inhabitants of the Canary Islands. In this study, we report the analysis of ten autosomal Alu insertion polymorphisms in 364 samples from the seven main islands of the Archipelago, and their comparison to continental samples. The detection of population-specific alleles from the Iberian Peninsula and Northwest Africa, as well as their affinities on the basis of genetic distances and principal component analysis, support a clear link between these populations. Coincident with previous results, the Canarian gene pool can be distinguished as being halfway between those of its putative parents, although with a major Iberian contribution (62-78%). Both the substantial Northwest African contribution (23-38%), and the minor sub-Saharan African input (3%), suggest that the genetic legacy from the aborigines and slaves still persists in the Canary Islanders.
Link
doi:10.1046/j.1529-8817.2003.00125.x
A Tale of Aborigines, Conquerors and Slaves: Alu Insertion Polymorphisms and the Peopling of Canary Islands
N. Maca-Meyer et al.
Summary
Classical, mitochondrial DNA (mtDNA) and Y chromosome markers have been used to examine the genetic admixture in present day inhabitants of the Canary Islands. In this study, we report the analysis of ten autosomal Alu insertion polymorphisms in 364 samples from the seven main islands of the Archipelago, and their comparison to continental samples. The detection of population-specific alleles from the Iberian Peninsula and Northwest Africa, as well as their affinities on the basis of genetic distances and principal component analysis, support a clear link between these populations. Coincident with previous results, the Canarian gene pool can be distinguished as being halfway between those of its putative parents, although with a major Iberian contribution (62-78%). Both the substantial Northwest African contribution (23-38%), and the minor sub-Saharan African input (3%), suggest that the genetic legacy from the aborigines and slaves still persists in the Canary Islanders.
Link