Nature Genetics 39, 1251 - 1255 (2007)
Published online: 9 September 2007 | doi:10.1038/ng2116
Measurement of the human allele frequency spectrum demonstrates greater genetic drift in East Asians than in Europeans
Alon Keinan et al.
Large data sets on human genetic variation have been collected recently, but their usefulness for learning about history and natural selection has been limited by biases in the ways polymorphisms were chosen. We report large subsets of SNPs from the International HapMap Project1, 2 that allow us to overcome these biases and to provide accurate measurement of a quantity of crucial importance for understanding genetic variation: the allele frequency spectrum. Our analysis shows that East Asian and northern European ancestors shared the same population bottleneck expanding out of Africa but that both also experienced more recent genetic drift, which was greater in East Asians.
Link
September 26, 2007
Anthropometric correlates of IQ
A reader alerted me to this study which re-examined Hooton's data on anthropometric correlates of IQ. Interestingly, sitting height correlates with IQ almost as strongly as (full) height, indicating that a long torso rather than long limbs is associated with statistically higher IQ.
Personality and Individual Differences
doi:10.1016/j.paid.2007.07.013
Head size correlates with IQ in a sample of Hooton’s criminal data
Jeremy E.C. Genovese
Abstract
Data collected by Hooton (1939) on 676 inmates held at the Concord Reformatory in Massachusetts include both anthropometric measures and IQ scores. In this study a sample (N = 238) was drawn to assess the nonparametric correlation between measures of head size and IQ. Head length (r = .13), breadth (r = .15), height (r = .14), circumference (r = .15) and calculated volume (r = .20) correlated with IQ. Two measures of body size also correlated with IQ; height (r = .22) and sitting height (r = .19).
Link
Personality and Individual Differences
doi:10.1016/j.paid.2007.07.013
Head size correlates with IQ in a sample of Hooton’s criminal data
Jeremy E.C. Genovese
Abstract
Data collected by Hooton (1939) on 676 inmates held at the Concord Reformatory in Massachusetts include both anthropometric measures and IQ scores. In this study a sample (N = 238) was drawn to assess the nonparametric correlation between measures of head size and IQ. Head length (r = .13), breadth (r = .15), height (r = .14), circumference (r = .15) and calculated volume (r = .20) correlated with IQ. Two measures of body size also correlated with IQ; height (r = .22) and sitting height (r = .19).
Link
September 25, 2007
Deep voiced-men have more children
You might want to read the blog post on What is your voice pitch after reading this article.
Biology Letters
10.1098/rsbl.2007.0410
Voice pitch predicts reproductive success in male hunter-gatherers
C.L. Apicella et al.
The validity of evolutionary explanations of vocal sexual dimorphism hinges upon whether or not individuals with more sexually dimorphic voices have higher reproductive success than individuals with less dimorphic voices. However, due to modern birth control methods, these data are rarely described, and mating success is often used as a second-rate proxy. Here, we test whether voice pitch predicts reproductive success, number of children born and child mortality in an evolutionarily relevant population of hunter-gatherers. While we find that voice pitch is not related to reproductive outcomes in women, we find that men with low voice pitch have higher reproductive success and more children born to them. However, voice pitch in men does not predict child mortality. These findings suggest that the association between voice pitch and reproductive success in men is mediated by differential access to fecund women. Furthermore, they show that there is currently selection pressure for low-pitch voices in men.
Link
Biology Letters
10.1098/rsbl.2007.0410
Voice pitch predicts reproductive success in male hunter-gatherers
C.L. Apicella et al.
The validity of evolutionary explanations of vocal sexual dimorphism hinges upon whether or not individuals with more sexually dimorphic voices have higher reproductive success than individuals with less dimorphic voices. However, due to modern birth control methods, these data are rarely described, and mating success is often used as a second-rate proxy. Here, we test whether voice pitch predicts reproductive success, number of children born and child mortality in an evolutionarily relevant population of hunter-gatherers. While we find that voice pitch is not related to reproductive outcomes in women, we find that men with low voice pitch have higher reproductive success and more children born to them. However, voice pitch in men does not predict child mortality. These findings suggest that the association between voice pitch and reproductive success in men is mediated by differential access to fecund women. Furthermore, they show that there is currently selection pressure for low-pitch voices in men.
Link
September 06, 2007
YAP+ in South Asia
YAP+ defines haplogroup DE in the human Y chromosome phylogeny. Haplogroup D seems confined to a few Asian populations whereas haplogroup E is found in Africans and West Eurasians. Previous studies had determined that D is found at high frequencies among the short-statured isolated populations from the Andaman and Nicobar islands, and this new study indicates that D is also found in mainland South Asia among tribal Indians, albeit at lower frequencies.
Ann Hum Biol. 2007 Sep-Oct;34(5):582-6
YAP insertion signature in South Asia.
Chandrasekar A et al.
A total of 2169 samples from 21 tribal populations from different regions of India were scanned for the Y-chromosome Alu polymorphism. This study reports, for the first time, high frequencies (8-65%) of Y Alu polymorphic (YAP) insertion in northeast Indian tribes. All seven Jarawa samples from the Andaman and Nicobar islands had the YAP insertion, in conformity with an earlier study of Andaman Islanders. One isolated case with haplotype E* was found in Dungri Bhill, a western Indian population, while YAP insertion in northeast India and Andaman tribes was found in association with haplotype D* (M168, M174). YAP insertion frequencies reported in the mainland Indian populations are negligible, according to previous studies. Genetic drift may be the causative factor for the variable frequency of the YAP insertion in the mainland populations, while the founder effect may have resulted in the highest incidence of haplotype D among the Andaman Islanders. The results of YAP insertion and the evidence of previous mtDNA studies indicate an early out of Africa migration to the Andaman and Nicobar Islands. The findings of YAP insertion in northeast Indian tribes are very significant for understanding the evolutionary history of the region.
Ann Hum Biol. 2007 Sep-Oct;34(5):582-6
YAP insertion signature in South Asia.
Chandrasekar A et al.
A total of 2169 samples from 21 tribal populations from different regions of India were scanned for the Y-chromosome Alu polymorphism. This study reports, for the first time, high frequencies (8-65%) of Y Alu polymorphic (YAP) insertion in northeast Indian tribes. All seven Jarawa samples from the Andaman and Nicobar islands had the YAP insertion, in conformity with an earlier study of Andaman Islanders. One isolated case with haplotype E* was found in Dungri Bhill, a western Indian population, while YAP insertion in northeast India and Andaman tribes was found in association with haplotype D* (M168, M174). YAP insertion frequencies reported in the mainland Indian populations are negligible, according to previous studies. Genetic drift may be the causative factor for the variable frequency of the YAP insertion in the mainland populations, while the founder effect may have resulted in the highest incidence of haplotype D among the Andaman Islanders. The results of YAP insertion and the evidence of previous mtDNA studies indicate an early out of Africa migration to the Andaman and Nicobar Islands. The findings of YAP insertion in northeast Indian tribes are very significant for understanding the evolutionary history of the region.
September 04, 2007
Middle Eastern origin of Neolithic pigs
Via the BBC Pig DNA reveals farming history:
Between 6,800-4,000 BC, farming methods spread across Europe, but the question of how these methods spread has not been fully established.
The two competing theories are that farming spread through cultural exchange, possibly during trading or that people migrated to Europe bringing their expertise with them.
A previous study, in 2005, analysed modern pig DNA and showed that all modern pigs are descended from European wild boar. This led researchers to conclude that early Europeans domesticated pigs independently of other farming methods.
This new study, however, has discovered that the first domesticated pigs in Europe did have Near Eastern ancestry, indicating that farmers migrated to Europe, bringing their "package" of livestock and farming methods with them.
Domestic pigs of European wild boar ancestry appear soon afterwards.
September 01, 2007
Structure of genetic variation in US populations
A new AJHG preprint looks at the genetic variation in different groups of the US population.
From the paper:
Stephen L. Guthery et al.
ABSTRACT
The common variant/common disease model predicts that most risk alleles underlying complex health-related traits are common and therefore old and found in multiple populations, rather than rare or population-specific. Accordingly, there is widespread interest in assessing the population structure of common alleles. However, such assessments have been confounded by analysis of datasets with bias toward ascertainment of common alleles (e.g., HapMap, Perlegen) or in which a relatively small number of genes and/or populations were sampled. The aim of this study was to examine the structure of common variation ascertained in major U.S. populations by resequencing the exons and flanking regions of 3,873 genes in 154 chromosomes from European, Latino/Hispanic, Asian, and African Americans generated by the Genaissance Resequencing Project. The frequency distributions of private and
common single nucleotide polymorphisms (SNPs) were measured, and the extent to which common SNPs were shared across populations was analyzed using several different estimators of population structure. Most SNPs that were common in one population were present in multiple populations, but SNPs common in one population were frequently not common in other populations. Moreover, SNPs that were common in two or more populations often differed significantly in frequency from one another, particularly in comparisons of African Americans versus other U.S. populations. These findings indicate that even if the bulk of alleles underlying complex health-related traits are common SNPs, geographic ancestry might well be an important predictor of whether a person carries a risk allele.
Link
From the paper:
A frequent claim about human population structure is that most common variationAlso an interesting view of the genetic structure of the main US population groups.
is shared among all populations11-13. This, of course, depends on how population
boundaries are defined, but often cited to support such comments are the comparisons of SNP frequencies in pairs of populations in the HapMap data and the Perlegen data. Analyses of these data indicated that common SNPs were frequently both shared and common among populations of predominately African, Asian, and European ancestry. However, population genetic analysis was not the intended goal of either the HapMap or the Perlegen projects, and common, shared SNPs were over sampled by the ascertainment strategies used for each project.
C. Stacked bar chart inferred from results of model-based cluster analysis using STRUCTURE 2.0. Each bar represents an individual, and each bar is divided according to the fraction of cluster membership. D. Triangle plot illustrating the proportion of African, Asian, and European American ancestry of each individual (dots) estimated from STRUCTURE 2.0. (PC=principal component; AfA=African American; AsA=Asian American; EA=European Americans; HA=Latino/Hispanic Americans; MAF=minor allele frequency.)The structure of common genetic variation in U.S. populations
Stephen L. Guthery et al.
ABSTRACT
The common variant/common disease model predicts that most risk alleles underlying complex health-related traits are common and therefore old and found in multiple populations, rather than rare or population-specific. Accordingly, there is widespread interest in assessing the population structure of common alleles. However, such assessments have been confounded by analysis of datasets with bias toward ascertainment of common alleles (e.g., HapMap, Perlegen) or in which a relatively small number of genes and/or populations were sampled. The aim of this study was to examine the structure of common variation ascertained in major U.S. populations by resequencing the exons and flanking regions of 3,873 genes in 154 chromosomes from European, Latino/Hispanic, Asian, and African Americans generated by the Genaissance Resequencing Project. The frequency distributions of private and
common single nucleotide polymorphisms (SNPs) were measured, and the extent to which common SNPs were shared across populations was analyzed using several different estimators of population structure. Most SNPs that were common in one population were present in multiple populations, but SNPs common in one population were frequently not common in other populations. Moreover, SNPs that were common in two or more populations often differed significantly in frequency from one another, particularly in comparisons of African Americans versus other U.S. populations. These findings indicate that even if the bulk of alleles underlying complex health-related traits are common SNPs, geographic ancestry might well be an important predictor of whether a person carries a risk allele.
Link
Problems with Neanderthal genomic sequences
A new study freely available online throws into doubt the genomic sequences extracted from Neanderthal remains in two previous articles.
PLoS Genetics
Inconsistencies in Neanderthal genomic DNA sequences
Jeffrey D. Wall, Sung K. Kim
Two recently published papers describe nuclear DNA sequences that were obtained from the same Neanderthal fossil. Our reanalyses of the data from these studies show that they are not consistent with each other and point to serious problems with the data quality in one of the studies, possibly due to modern human DNA contaminants and/or a high rate of sequencing errors.
Link
PLoS Genetics
Inconsistencies in Neanderthal genomic DNA sequences
Jeffrey D. Wall, Sung K. Kim
Two recently published papers describe nuclear DNA sequences that were obtained from the same Neanderthal fossil. Our reanalyses of the data from these studies show that they are not consistent with each other and point to serious problems with the data quality in one of the studies, possibly due to modern human DNA contaminants and/or a high rate of sequencing errors.
Link
August 19, 2007
Dispersal of haplogroup N from Siberia into Eastern Europe
J Hum Genet. 2007 Aug 17; [Epub ahead of print]
Y-chromosome haplogroup N dispersals from south Siberia to Europe.
Derenko M, Malyarchuk B, Denisova G, Wozniak M, Grzybowski T, Dambueva I, Zakharov I.
Y-chromosome haplogroup N dispersals from south Siberia to Europe.
Derenko M, Malyarchuk B, Denisova G, Wozniak M, Grzybowski T, Dambueva I, Zakharov I.
In order to reconstruct the history of Y-chromosome haplogroup (hg) N dispersals in north Eurasia, we have analyzed the diversity of microsatellite (STR) loci within two major hg N clades, N2 and N3, in a total sample of 1,438 males from 17 ethnic groups, mainly of Siberian and Eastern European origin. Based on STR variance analysis we observed that hg N3a is more diverse in Eastern Europe than in south Siberia. However, analysis of median networks showed that there are two STR subclusters of hg N3a, N3a1 and N3a2, that are characterized by different genetic histories. Age calculation of STR variation within subcluster N3a1 indicated that its first expansion occurred in south Siberia [approximately 10,000 years (ky)] and then this subcluster spread into Eastern Europe where its age is around 8 ky ago. Meanwhile, younger subcluster N3a2 originated in south Siberia (probably in the Baikal region) approximately 4 ky ago. Median network and variance analyses of STR haplotypes suggest that south Siberian N3a2 haplotypes spread further into Volga-Ural region undergoing serial bottlenecks. In addition, median network analysis of STR data demonstrates that haplogroup N2-A is represented by two subclusters, showing recent expansion times. The data obtained allow us to suggest Siberian origin of haplogroups N3 and N2 that are currently widespread in some populations of Eastern Europe.
Link
August 15, 2007
The new Ming the Merciless
I haven't watched the new incarnation of Flash Gordon on SCI-FI Channel, but can anyone spot a difference between the Ming character from the 1930s serial and last FG movie and the newest one?
Hypothesis about the origins of hemochromatosis
Med Hypotheses. 2007 Aug 7; [Epub ahead of print]
Hemochromatosis: A Neolithic adaptation to cereal grain diets.
Naugler C.
The Neolithic period in Europe marked the transition from a hunter-gatherer diet rich in red meat to an iron-reduced cereal grain diet. This dietary shift likely resulted in an increased incidence of iron deficiency anemia, especially in women of reproductive age. I propose that hereditary hemochromatosis and in particular the common HFE C282Y mutation may represent an adaptation to decreased dietary iron in cereal grain-based Neolithic diets. Both homozygous and heterozygous carriers of the HFE C282Y mutation have increased iron stores and therefore possessed an adaptive advantage under Neolithic conditions. An allele age estimate places the origin of the HFE C282Y mutation in the early Neolithic period in Northern Europe and is thus consistent with this hypothesis. The lower incidence of this mutation in other agrarian regions (the Mediterranean and Near East) may be due to higher dietary intakes of the iron uptake cofactor vitamin C in those regions. The HFE C282Y mutation likely only became maladaptive in the past several centuries as dietary sources of iron and vitamin C improved in Northern Europe.
Link
Hemochromatosis: A Neolithic adaptation to cereal grain diets.
Naugler C.
The Neolithic period in Europe marked the transition from a hunter-gatherer diet rich in red meat to an iron-reduced cereal grain diet. This dietary shift likely resulted in an increased incidence of iron deficiency anemia, especially in women of reproductive age. I propose that hereditary hemochromatosis and in particular the common HFE C282Y mutation may represent an adaptation to decreased dietary iron in cereal grain-based Neolithic diets. Both homozygous and heterozygous carriers of the HFE C282Y mutation have increased iron stores and therefore possessed an adaptive advantage under Neolithic conditions. An allele age estimate places the origin of the HFE C282Y mutation in the early Neolithic period in Northern Europe and is thus consistent with this hypothesis. The lower incidence of this mutation in other agrarian regions (the Mediterranean and Near East) may be due to higher dietary intakes of the iron uptake cofactor vitamin C in those regions. The HFE C282Y mutation likely only became maladaptive in the past several centuries as dietary sources of iron and vitamin C improved in Northern Europe.
Link
New YHRD release
An August 10 release of the YHRD - Y Chromosome Haplotype Reference Database.
Twenty populations were added or updated today: two Amerindian tribal populations from the Formosa province in Argentina (Pilaga, Toba), one from Venezuela (Caracas), two from provinces in Colombia (Boyaca, Cundinamarca), three from Siberian nomad populations (Western and Central Evens, Iengra Evenks), one from Belarus (Pinsk), three from Ukraine (Kiev, Lviv, Lugansk), three populations from Capetown in South Africa, three from Ravenna, Rimini and Val Marecchia in Italy, one from Hungary, one from Peru and one from Oran in Algeria.
August 04, 2007
Mating patterns amongst Siberian reindeer hunters
Am J Phys Anthropol. 2007 Jul;133(3):1013-27
Mating patterns amongst Siberian reindeer herders: inferences from mtDNA and Y-chromosomal analyses.
Pakendorf B, Novgorodov IN, Osakovskij VL, Stoneking M.
The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka-Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neighbors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y-chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y-haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y-chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult.
Link
Mating patterns amongst Siberian reindeer herders: inferences from mtDNA and Y-chromosomal analyses.
Pakendorf B, Novgorodov IN, Osakovskij VL, Stoneking M.
The Evenks and Evens, who speak closely related languages belonging to the Northern Tungusic branch of the Tungusic family, are nomadic reindeer herders and hunters. They are spread over an immense territory in northeastern Siberia, and consequently different subgroups are in contact with diverse peoples speaking Samoyedic, Turkic, Mongolic, Chukotka-Kamchatkan, and Yukaghir languages. Nevertheless, the languages and culture of the Evenks and Evens are similar enough for them to have been classified as a single ethnic group in the past. This linguistic and cultural similarity indicates that they may have spread over their current area of habitation relatively recently, and thus may be closely related genetically. On the other hand, the great distances that separate individual groups of Evens and Evenks from each other might have led to preferential mating with geographic neighbors rather than with linguistically related peoples. In this study, we assess the correlation between linguistic and genetic relationship in three different subgroups of Evenks and Evens, respectively, via mtDNA and Y-chromosomal analyses. The results show that there is some evidence of a common origin based on shared mtDNA lineages and relatively similar Y-haplogroup frequencies amongst most of the Evenk and Even subgroups. However, there is little sharing of Y-chromosomal STR haplotypes, indicating that males within Evenk and Even subgroups have remained relatively isolated. There is further evidence of some female admixture in different Even subgroups with their respective geographic neighbors. However, the Tungusic groups, and especially the Evenks, show signs of genetic drift, making inferences about their prehistory difficult.
Link
August 01, 2007
Y chromosomes of Guinea-Bissau
BMC Evol Biol. 2007 Jul 27;7(1):124. [Epub ahead of print]
Y-chromosomal diversity in the population of Guinea-Bissau: a multiethnic
perspective.
Rosa A, Ornelas C, Jobling MA, Brehm A, Villems R.
ABSTRACT: BACKGROUND: The geographic and ethnolinguistic differentiation of many African Y-chromosomal lineages provides an opportunity to evaluate human migration episodes and admixture processes, in a pan-continental context. The
analysis of the paternal genetic structure of Equatorial West Africans carried out to date leaves their origins and relationships unclear, and raises questions about the existence of major demographic phenomena analogous to the large-scale
Bantu expansions. To address this, we have analysed the variation of 31 binary and 11 microsatellite markers on the non-recombining portion of the Y chromosome in Guinea-Bissau samples of diverse ethnic affiliations, some not studied before.
RESULTS: The Guinea-Bissau Y chromosome pool is characterized by low haplogroup diversity (D=0.470, sd 0.033), with the predominant haplogroup E3a*-M2 shared among the ethnic clusters and reaching a maximum of 82.2% in the Mandenka people. The Felupe-Djola and Papel groups exhibit the highest diversity of lineages and harbor the deep-rooting haplogroups A-M91, E2-M75 and E3*-PN2, typical of Sahel's more central and eastern areas. Their genetic distinction from other groups is
statistically significant (P=0.01) though not attributable to linguistic, geographic or religious criteria. Non sub-Saharan influences were associated with the presence of haplogroup R1b-P25 and particular lineages of E3b1-M78.
CONCLUSIONS: The predominance and high diversity of haplogroup E3a*-M2 suggests a demographic expansion in the equatorial western fringe, possibly supported by a local agricultural center. The paternal pool of the Mandenka and Balanta displays evidence of a particularly marked population growth among the Guineans, possibly reflecting the demographic effects of the agriculturalist lifestyle and their putative relationship to the people that introduced early cultivation practices
into West Africa. The paternal background of the Felupe-Djola and Papel ethnic groups suggests a better conserved ancestral pool deriving from East Africa, from where they have supposedly migrated in recent times. Despite the overall
homogeneity in a multiethnic sample, which contrasts with their social structure, minor clusters suggest the imprints of multiple peoples at different timescales: traces of ancestral inhabitants in haplogroups A-M91 and B-M60, today typical of
hunter-gatherers; North African influence in E3b1-M78 Y chromosomes, probably due to trans-Saharan contacts; and R1b-P25 lineages reflecting European admixture via the North Atlantic slave trade.
Link
Y-chromosomal diversity in the population of Guinea-Bissau: a multiethnic
perspective.
Rosa A, Ornelas C, Jobling MA, Brehm A, Villems R.
ABSTRACT: BACKGROUND: The geographic and ethnolinguistic differentiation of many African Y-chromosomal lineages provides an opportunity to evaluate human migration episodes and admixture processes, in a pan-continental context. The
analysis of the paternal genetic structure of Equatorial West Africans carried out to date leaves their origins and relationships unclear, and raises questions about the existence of major demographic phenomena analogous to the large-scale
Bantu expansions. To address this, we have analysed the variation of 31 binary and 11 microsatellite markers on the non-recombining portion of the Y chromosome in Guinea-Bissau samples of diverse ethnic affiliations, some not studied before.
RESULTS: The Guinea-Bissau Y chromosome pool is characterized by low haplogroup diversity (D=0.470, sd 0.033), with the predominant haplogroup E3a*-M2 shared among the ethnic clusters and reaching a maximum of 82.2% in the Mandenka people. The Felupe-Djola and Papel groups exhibit the highest diversity of lineages and harbor the deep-rooting haplogroups A-M91, E2-M75 and E3*-PN2, typical of Sahel's more central and eastern areas. Their genetic distinction from other groups is
statistically significant (P=0.01) though not attributable to linguistic, geographic or religious criteria. Non sub-Saharan influences were associated with the presence of haplogroup R1b-P25 and particular lineages of E3b1-M78.
CONCLUSIONS: The predominance and high diversity of haplogroup E3a*-M2 suggests a demographic expansion in the equatorial western fringe, possibly supported by a local agricultural center. The paternal pool of the Mandenka and Balanta displays evidence of a particularly marked population growth among the Guineans, possibly reflecting the demographic effects of the agriculturalist lifestyle and their putative relationship to the people that introduced early cultivation practices
into West Africa. The paternal background of the Felupe-Djola and Papel ethnic groups suggests a better conserved ancestral pool deriving from East Africa, from where they have supposedly migrated in recent times. Despite the overall
homogeneity in a multiethnic sample, which contrasts with their social structure, minor clusters suggest the imprints of multiple peoples at different timescales: traces of ancestral inhabitants in haplogroups A-M91 and B-M60, today typical of
hunter-gatherers; North African influence in E3b1-M78 Y chromosomes, probably due to trans-Saharan contacts; and R1b-P25 lineages reflecting European admixture via the North Atlantic slave trade.
Link
July 30, 2007
Click language speakers share deep not recent common ancestry
Mol Biol Evol. 2007 Jul 26; [Epub ahead of print]
History of Click-Speaking Populations of Africa Inferred from mtDNA and Y Chromosome Genetic Variation.
Tishkoff SA et al.
Little is known about the history of click-speaking populations in Africa. Prior genetic studies revealed that the click-speaking Hadza of eastern Africa are as distantly related to click speakers of southern Africa as are most other African populations. The Sandawe, who currently live within 150 km of the Hadza, are the only other population in eastern Africa whose language has been classified as part of the Khoisan language family. Linguists disagree on whether there is any detectable relationship between the Hadza and Sandawe click languages. We characterized both mtDNA and Y chromosome variation of the Sandawe, Hadza, and neighboring Tanzanian populations. New genetic data show that the Sandawe and southern African click speakers share rare mtDNA and Y chromosome haplogroups; however, common ancestry of the two populations dates back >35,000 years. These data also indicate that common ancestry of the Hadza and Sandawe populations dates back >15,000 years. These findings suggest that at the time of the spread of agriculture and pastoralism, the click-speaking populations were already isolated from one another, and are consistent with relatively deep linguistic divergence among the respective click languages.
Link
History of Click-Speaking Populations of Africa Inferred from mtDNA and Y Chromosome Genetic Variation.
Tishkoff SA et al.
Little is known about the history of click-speaking populations in Africa. Prior genetic studies revealed that the click-speaking Hadza of eastern Africa are as distantly related to click speakers of southern Africa as are most other African populations. The Sandawe, who currently live within 150 km of the Hadza, are the only other population in eastern Africa whose language has been classified as part of the Khoisan language family. Linguists disagree on whether there is any detectable relationship between the Hadza and Sandawe click languages. We characterized both mtDNA and Y chromosome variation of the Sandawe, Hadza, and neighboring Tanzanian populations. New genetic data show that the Sandawe and southern African click speakers share rare mtDNA and Y chromosome haplogroups; however, common ancestry of the two populations dates back >35,000 years. These data also indicate that common ancestry of the Hadza and Sandawe populations dates back >15,000 years. These findings suggest that at the time of the spread of agriculture and pastoralism, the click-speaking populations were already isolated from one another, and are consistent with relatively deep linguistic divergence among the respective click languages.
Link
Ancient Chinese Y chromosomes
Another paper on ancient Y-DNA, it seems like the times where we could only expect to get mtDNA from prehistoric remains is coming to a close.
Hum Genet. 2007 Jul 27; [Epub ahead of print]
Y chromosomes of prehistoric people along the Yangtze River.
Li H et al.
The ability to extract mitochondrial and nuclear DNA from ancient remains has enabled the study of ancient DNA, a legitimate field for over 20 years now. Recently, Y chromosome genotyping has begun to be applied to ancient DNA. The Y chromosome haplogroup in East Asia has since caught the attention of molecular anthropologists, as it is one of the most ethnic-related genetic markers of the region. In this paper, the Y chromosome haplogroup of DNA from ancient East Asians was examined, in order to genetically link them to modern populations. Fifty-six human remains were sampled from five archaeological sites, primarily along the Yangtze River. Strict criteria were followed to eliminate potential contamination. Five SNPs from the Y chromosome were successfully amplified from most of the samples, with at least 62.5% of the samples belonging to the O haplogroup, similar to the frequency for modern East Asian populations. A high frequency of O1 was found in Liangzhu Culture sites around the mouth of the Yangtze River, linking this culture to modern Austronesian and Daic populations. A rare haplogroup, O3d, was found at the Daxi site in the middle reaches of the Yangtze River, indicating that the Daxi people might be the ancestors of modern Hmong-Mien populations, which show only small traces of O3d today. Noticeable genetic segregation was observed among the prehistoric cultures, demonstrating the genetic foundation of the multiple origins of the Chinese Civilization.
Link
Hum Genet. 2007 Jul 27; [Epub ahead of print]
Y chromosomes of prehistoric people along the Yangtze River.
Li H et al.
The ability to extract mitochondrial and nuclear DNA from ancient remains has enabled the study of ancient DNA, a legitimate field for over 20 years now. Recently, Y chromosome genotyping has begun to be applied to ancient DNA. The Y chromosome haplogroup in East Asia has since caught the attention of molecular anthropologists, as it is one of the most ethnic-related genetic markers of the region. In this paper, the Y chromosome haplogroup of DNA from ancient East Asians was examined, in order to genetically link them to modern populations. Fifty-six human remains were sampled from five archaeological sites, primarily along the Yangtze River. Strict criteria were followed to eliminate potential contamination. Five SNPs from the Y chromosome were successfully amplified from most of the samples, with at least 62.5% of the samples belonging to the O haplogroup, similar to the frequency for modern East Asian populations. A high frequency of O1 was found in Liangzhu Culture sites around the mouth of the Yangtze River, linking this culture to modern Austronesian and Daic populations. A rare haplogroup, O3d, was found at the Daxi site in the middle reaches of the Yangtze River, indicating that the Daxi people might be the ancestors of modern Hmong-Mien populations, which show only small traces of O3d today. Noticeable genetic segregation was observed among the prehistoric cultures, demonstrating the genetic foundation of the multiple origins of the Chinese Civilization.
Link
July 27, 2007
Phylogeography of African Brazilians
Hum Hered. 2008 Jul 25;65(1):23-32 [Epub ahead of print]
The Phylogeography of African Brazilians.
Gonçalves VF, Carvalho CM, Bortolini MC, Bydlowski SP, Pena SD.
Gonçalves VF, Carvalho CM, Bortolini MC, Bydlowski SP, Pena SD.
Background/Aims: Approximately four million Africans were taken as slaves to Brazil, where they interbred extensively with Amerindians and Europeans. We have previously shown that while most White Brazilians carry Y chromosomes of European origin, they display high proportions of African and Amerindian mtDNA lineages, because of sex-biased genetic admixture. Methods: We studied the Y chromosome and mtDNA haplogroup structure of 120 Black males from Sao Paulo, Brazil. Results: Only 48% of the Y chromosomes, but 85% of the mtDNA haplogroups were characteristic of sub-Saharan Africa, confirming our previous observation of sexually biased mating. We mined literature data for mtDNA and Y chromosome haplogroup frequencies for African native populations from regions involved in Atlantic Slave Trade. Principal Components Analysis and Bayesian analysis of population structure revealed no genetic differentiation of Y chromosome marker frequencies between the African regions. However, mtDNA examination unraveled considerable genetic structure, with three clusters at Central-West Africa, West Africa and Southeast Africa. A hypothesis is proposed to explain this structure. Conclusion: Using these mtDNA data we could obtain for the first time an estimate of the relative ancestral contribution of Central-West (0.445), West (0.431) and Southeast Africa (0.123) to African Brazilians from Sao Paulo. These estimates are consistent with historical information. Copyright (c) 2008 S. Karger AG, Basel.
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