May 30, 2015

Out of Egypt or Out of Ethiopia?

I am skeptical that once you remove non-African ancestry from Egyptians (even if you were able to do so perfectly), what you are left with is indigenous Northeastern Africans, the direct descendants of people who left Africa tens of thousands of years ago.

For one thing, Egypt has not only experienced gene flow from Europe and the Middle East, but also from elsewhere in Africa, more recently because of enslaved black Africans.

For another, even if you perfectly identified and removed both Eurasian and African non-native influences on the Egyptian population, you're left with some kind of indigenous northeastern African. But, did such a population with long-term continuity exist in Egypt since Out-of-Africa? The Eurasian experience (where ancient DNA falsifies continuity left and right even in a 1/10th of the OOA time scale) makes me doubt this. The Nile may have facilitated gene flow in a north-south direction, and the relatively recent emergence of the Sahara desert may very well have pumped populations into Egypt.


Tracing the Route of Modern Humans out of Africa by Using 225 Human Genome Sequences from Ethiopians and Egyptians

Luca Pagani et al.

The predominantly African origin of all modern human populations is well established, but the route taken out of Africa is still unclear. Two alternative routes, via Egypt and Sinai or across the Bab el Mandeb strait into Arabia, have traditionally been proposed as feasible gateways in light of geographic, paleoclimatic, archaeological, and genetic evidence. Distinguishing among these alternatives has been difficult. We generated 225 whole-genome sequences (225 at 8× depth, of which 8 were increased to 30×; Illumina HiSeq 2000) from six modern Northeast African populations (100 Egyptians and five Ethiopian populations each represented by 25 individuals). West Eurasian components were masked out, and the remaining African haplotypes were compared with a panel of sub-Saharan African and non-African genomes. We showed that masked Northeast African haplotypes overall were more similar to non-African haplotypes and more frequently present outside Africa than were any sets of haplotypes derived from a West African population. Furthermore, the masked Egyptian haplotypes showed these properties more markedly than the masked Ethiopian haplotypes, pointing to Egypt as the more likely gateway in the exodus to the rest of the world. Using five Ethiopian and three Egyptian high-coverage masked genomes and the multiple sequentially Markovian coalescent (MSMC) approach, we estimated the genetic split times of Egyptians and Ethiopians from non-African populations at 55,000 and 65,000 years ago, respectively, whereas that of West Africans was estimated to be 75,000 years ago. Both the haplotype and MSMC analyses thus suggest a predominant northern route out of Africa via Egypt.


May 21, 2015

More Y-chromosome super-fathers

The time estimates are based on a mutation rate of 1x10-9 mutations/bp/year which is ~1/3 higher than mutation rate of Karmin et al.  So the values on the table may be a little lower.

There may be additional founders with recent time depths than shown in the table, e.g., a very shallow clusters within E-M35 (probably E-V13?) and a couple of shallow clusters within I-P215

Also of interest is the fact that Greeks and Anatolian Turks do not show evidence of the recent Y-chromosomal bottleneck:
The plots are consistent with patterns seen in the relative numbers of singletons, described above, in that the Saami and Palestinians show markedly different demographic histories compared with the rest, featuring very recent reductions, while the Turks and Greeks show evidence of general expansion, with increased growth rate around 14 KYA. A different pattern is seen in the remaining majority (13/17) of populations, which share remarkably similar histories featuring a minimum effective population size ~2.1–4.2 KYA (considering the 95% confidence intervals (CIs) reported in Supplementary Table 4), followed by expansion to the present.

Nature Communications 6, Article number: 7152 doi:10.1038/ncomms8152

Large-scale recent expansion of European patrilineages shown by population resequencing

Chiara Batini, Pille Hallast et al.

The proportion of Europeans descending from Neolithic farmers ~10 thousand years ago (KYA) or Palaeolithic hunter-gatherers has been much debated. The male-specific region of the Y chromosome (MSY) has been widely applied to this question, but unbiased estimates of diversity and time depth have been lacking. Here we show that European patrilineages underwent a recent continent-wide expansion. Resequencing of 3.7 Mb of MSY DNA in 334 males, comprising 17 European and Middle Eastern populations, defines a phylogeny containing 5,996 single-nucleotide polymorphisms. Dating indicates that three major lineages (I1, R1a and R1b), accounting for 64% of our sample, have very recent coalescent times, ranging between 3.5 and 7.3 KYA. A continuous swathe of 13/17 populations share similar histories featuring a demographic expansion starting ~2.1–4.2 KYA. Our results are compatible with ancient MSY DNA data, and contrast with data on mitochondrial DNA, indicating a widespread male-specific phenomenon that focuses interest on the social structure of Bronze Age Europe.


May 13, 2015

Neandertal in the (immediate) family tree

Early European may have had Neanderthal great-great-grandparent
One of Europe’s earliest known humans had a close Neanderthal ancestor: perhaps as close as a great-great-grandparent.

The finding, announced on 8 May at the Biology of Genomes meeting in Cold Spring Harbor, New York, questions the idea that humans and Neanderthals interbred only in the Middle East, more than 50,000 years ago.

Qiaomei Fu, a palaeogenomicist at Harvard Medical School in Boston, Massachusetts, told the meeting how she and her colleagues had sequenced DNA from a 40,000-year-old jawbone that represents some of the earliest modern-human remains in Europe. They estimate that 5–11% of the bone's genome is Neanderthal, including large chunks of several chromosomes. (The genetic analysis also shows that the individual was a man). By analysing how lengths of DNA inherited from any one ancestor shorten with each generation, the team estimated that the man had a Neanderthal ancestor in the previous 4–6 generations. (The researchers declined to comment on the work because it has not yet been published in a journal).

May 12, 2015

mtDNA haplogroup A10 in Bronze Age West Siberia

PLoS ONE 10(5): e0127182. doi:10.1371/journal.pone.0127182

MtDNA Haplogroup A10 Lineages in Bronze Age Samples Suggest That Ancient Autochthonous Human Groups Contributed to the Specificity of the Indigenous West Siberian Population

Aleksandr S. Pilipenko et al.



The craniometric specificity of the indigenous West Siberian human populations cannot be completely explained by the genetic interactions of the western and eastern Eurasian groups recorded in the archaeology of the area from the beginning of the 2nd millennium BC. Anthropologists have proposed another probable explanation: contribution to the genetic structure of West Siberian indigenous populations by ancient human groups, which separated from western and eastern Eurasian populations before the final formation of their phenotypic and genetic features and evolved independently in the region over a long period of time. This hypothesis remains untested. From the genetic point of view, it could be confirmed by the presence in the gene pool of indigenous populations of autochthonous components that evolved in the region over long time periods. The detection of such components, particularly in the mtDNA gene pool, is crucial for further clarification of early regional genetic history.

Results and Conclusion

We present the results of analysis of mtDNA samples (n = 10) belonging to the A10 haplogroup, from Bronze Age populations of West Siberian forest-steppe (V—I millennium BC), that were identified in a screening study of a large diachronic sample (n = 96). A10 lineages, which are very rare in modern Eurasian populations, were found in all the Bronze Age groups under study. Data on the A10 lineages’ phylogeny and phylogeography in ancient West Siberian and modern Eurasian populations suggest that A10 haplogroup underwent a long-term evolution in West Siberia or arose there autochthonously; thus, the presence of A10 lineages indicates the possible contribution of early autochthonous human groups to the genetic specificity of modern populations, in addition to contributions of later interactions of western and eastern Eurasian populations.


May 07, 2015

2,500-year old Etruscans

From a Biology of Genomes poster (pdf) on "Assessment of Whole-Genome capture methodologies on single- and double-stranded ancient DNA libraries from Caribbean and European archaeological human remains" by Ávila-Arcos et al.

All that can be said based on this is that they seem broadly southern European and not particularly Tuscan.

May 04, 2015

Ancient mtDNA from Neolithic France

PLoS ONE 10(4): e0125521. doi:10.1371/journal.pone.0125521

When the Waves of European Neolithization Met: First Paleogenetic Evidence from Early Farmers in the Southern Paris Basin

Maïté Rivollat et al.

An intense debate concerning the nature and mode of Neolithic transition in Europe has long received much attention. Recent publications of paleogenetic analyses focusing on ancient European farmers from Central Europe or the Iberian Peninsula have greatly contributed to this debate, providing arguments in favor of major migrations accompanying European Neolithization and highlighting noticeable genetic differentiation between farmers associated with two archaeologically defined migration routes: the Danube valley and the Mediterranean Sea. The aim of the present study was to fill a gap with the first paleogenetic data of Neolithic settlers from a region (France) where the two great currents came into both direct and indirect contact with each other. To this end, we analyzed the Gurgy 'Les Noisats' group, an Early/Middle Neolithic necropolis in the southern part of the Paris Basin. Interestingly, the archaeological record from this region highlighted a clear cultural influence from the Danubian cultural sphere but also notes exchanges with the Mediterranean cultural area. To unravel the processes implied in these cultural exchanges, we analyzed 102 individuals and obtained the largest Neolithic mitochondrial gene pool so far (39 HVS-I mitochondrial sequences and haplogroups for 55 individuals) from a single archaeological site from the Early/Middle Neolithic period. Pairwise FST values, haplogroup frequencies and shared informative haplotypes were calculated and compared with ancient and modern European and Near Eastern populations. These descriptive analyses provided patterns resulting from different evolutionary scenarios; however, the archaeological data available for the region suggest that the Gurgy group was formed through equivalent genetic contributions of farmer descendants from the Danubian and Mediterranean Neolithization waves. However, these results, that would constitute the most ancient genetic evidence of admixture between farmers from both Central and Mediterranean migration routes in the European Neolithization debate, are subject to confirmation through appropriate model-based approaches.


Facial reconstruction of Lord of Moken

I wonder when we will start seeing facial reconstructions that make use of ancient DNA. Ancient DNA isn't very good for reconstructing facial features, but it should be quite good at reconstructing pigmentation.

Facial reconstruction for 1,400-year-old 'Lord of Morken'
The man's remains were discovered in 1955 in a Franconian burial ground in Morken, near Cologne. He had been interred around the year 600 AD in a royal burial chamber there. The precious goods within the grave, especially the materials used for his weapons, suggest that the man enjoyed a special status in the population, Elke Nieveler a specialist for the early Middle Ages at the Rheinisches Landesmuseum said.

May 03, 2015

Modern humans, not Neandertals made the Proto-Aurignacian

Science DOI: 10.1126/science.aaa2773

The makers of the Protoaurignacian and implications for Neandertal extinction

S. Benazzi et al.

The Protoaurignacian culture is pivotal to the debate about the timing of the arrival of modern humans in Western Europe and the demise of Neandertals. However, which group is responsible for this culture remains uncertain. We investigated dental remains associated with the Protoaurignacian. The lower deciduous incisor from Riparo Bombrini is modern human, based on its morphology. The upper deciduous incisor from Grotta di Fumane contains ancient mitochondrial DNA of a modern human type. These teeth are the oldest human remains in an Aurignacian-related archeological context, confirming that by 41,000 calendar years before the present, modern humans bearing Protoaurignacian culture spread into Southern Europe. Because the last Neandertals date to 41,030 to 39,260 calendar years before the present, we suggest that the Protoaurignacian triggered the demise of Neandertals in this area.


Structure of Y-haplogroup N

arXiv:1504.06463 [q-bio.PE]

The dichotomy structure of Y chromosome Haplogroup N

Kang Hu et al.

Haplogroup N-M231 of human Y chromosome is a common clade from Eastern Asia to Northern Europe, being one of the most frequent haplogroups in Altaic and Uralic-speaking populations. Using newly discovered bi-allelic markers from high-throughput DNA sequencing, we largely improved the phylogeny of Haplogroup N, in which 16 subclades could be identified by 33 SNPs. More than 400 males belonging to Haplogroup N in 34 populations in China were successfully genotyped, and populations in Northern Asia and Eastern Europe were also compared together. We found that all the N samples were typed as inside either clade N1-F1206 (including former N1a-M128, N1b-P43 and N1c-M46 clades), most of which were found in Altaic, Uralic, Russian and Chinese-speaking populations, or N2-F2930, common in Tibeto-Burman and Chinese-speaking populations. Our detailed results suggest that Haplogroup N developed in the region of China since the final stage of late Paleolithic Era.


Southern origins and recent admixture of Siberian populations


The complex admixture history and recent southern origins of Siberian populations

Irina Pugach , Rostislav Matveev , Viktor Spitsyn , Sergey Makarov , Innokentiy Novgorodov , Vladimir Osakovsky , Mark Stoneking , Brigitte Pakendorf

Although Siberia was inhabited by modern humans at an early stage, there is still debate over whether this area remained habitable during the extremely cold period of the Last Glacial Maximum or whether it was subsequently repopulated by peoples with a recent shared ancestry. Previous studies of the genetic history of Siberian populations were hampered by the extensive admixture that appears to have taken place among these populations, since commonly used methods assume a tree-like population history and at most single admixture events. We therefore developed a new method based on the covariance of ancestry components, which we validated with simulated data, in order to investigate this potentially complex admixture history and to distinguish the effects of shared ancestry from prehistoric migrations and contact. We furthermore adapted a previously devised method of admixture dating for use with multiple events of gene flow, and applied these methods to whole-genome genotype data from over 500 individuals belonging to 20 different Siberian ethnolinguistic groups. The results of these analyses indicate that there have indeed been multiple layers of admixture detectable in most of the Siberian populations, with considerable differences in the admixture histories of individual populations, and with the earliest events dated to not more than 4500 years ago. Furthermore, most of the populations of Siberia included here, even those settled far to the north, can be shown to have a southern origin. These results provide support for a recent population replacement in this region, with the northward expansions of different populations possibly being driven partly by the advent of pastoralism, especially reindeer domestication. These newly developed methods to analyse multiple admixture events should aid in the investigation of similarly complex population histories elsewhere.


Eye color and alcohol dependence

American Journal of Medical Genetics Part B: Neuropsychiatric Genetics DOI: 10.1002/ajmg.b.32316

Eye color: A potential indicator of alcohol dependence risk in European Americans

Arvis Sulovari et al.

In archival samples of European-ancestry subjects, light-eyed individuals have been found to consume more alcohol than dark-eyed individuals. No published population-based studies have directly tested the association between alcohol dependence (AD) and eye color. We hypothesized that light-eyed individuals have a higher prevalence of AD than dark-eyed individuals. A mixture model was used to select a homogeneous sample of 1,263 European-Americans and control for population stratification. After quality control, we conducted an association study using logistic regression, adjusting for confounders (age, sex, and genetic ancestry). We found evidence of association between AD and blue eye color (P = 0.0005 and odds ratio = 1.83 (1.31–2.57)), supporting light eye color as a risk factor relative to brown eye color. Network-based analyses revealed a statistically significant (P = 0.02) number of genetic interactions between eye color genes and AD-associated genes. We found evidence of linkage disequilibrium between an AD-associated GABA receptor gene cluster, GABRB3/GABRG3, and eye color genes, OCA2/HERC2, as well as between AD-associated GRM5 and pigmentation-associated TYR. Our population-phenotype, network, and linkage disequilibrium analyses support association between blue eye color and AD. Although we controlled for stratification we cannot exclude underlying occult stratification as a contributor to this observation. Although replication is needed, our findings suggest that eye pigmentation information may be useful in research on AD. Further characterization of this association may unravel new AD etiological factors. © 2015 Wiley Periodicals, Inc.