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
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