Visualizing Y-haplogroup distributions in west Eurasia

From the paper:

The database contains distributions representing 90 populations (N = 16,751 males) by the frequencies of the published and unpublished Y-chromosome Hgs. These Hgs were combined into 18 different Hgs (C, E, ABDF*, G, H, I1, I2, J1, J2, K*, L, N, O, Q, R1a, R1b, R2, T), so that published sources could be used for comparisons. 

... 

As shown in Fig. 1, Middle Eastern (Class 7) and Central European Classes (Class 8) form one non-separable cluster in the central part of the figure. All of the others of the 10 classes can be identified in different well separable areas around this central region. The Central Asian (Class 4) and Northwest Caucasian (Class 9) Classes are in neighbouring areas in the upper and upper-left parts, while the Arab-Dagestanian Class (Class 1) occupies the opposite, lower-left part of the map. The North-Central and Western European (Class 3 + Class 6) as well as the Atlantic (Class 10) Classes form a common branch in the lower-left part of the figure. The opposite, upper-right branch contains the East Baltic (Class 5) and North Eurasian (Class 2) Classes.

Forensic Science International: Genetics Supplement SeriesAvailable online 26 October 2013

Classification of the Y-haplogroup distributions of Western Eurasian populations using a self-learning algorithm

H. Pamjav et al.

The understanding of historical relationship between populations is a core aspect of human population history studies. We have compared the frequency of 18 different Y-SNP haplogroups in 90 Western Eurasian populations. Classification of haplogroup distribution vectors using a new self-learning classification algorithm so called “self-organizing cloud (SOC)” proved to be an effective tool to identify population groups, which share common paternal genetic features. By means of the algorithm, we have determined 10 different classes of populations based on the similarity of haplogroup composition. The analysis showed that paternal genetic markers tend to reflect geographical proximity of populations better than linguistic relationship, although certain Y-SNP haplogroups have relatively good correlation with specific language families. These observations are based on the comparative analysis of the Hg distributions of contemporary populations may reflect demographic history of them in the past.

Link

Intra-African variation in Neandertal admixture is due to non-African admixture

I haven't read this, but the idea seems to be that variation between Africans in Neandertal admixture can be wholly explained by recent admixture with Eurasians (who already had this type of admixture). This is not very surprising, given that Neandertals were a Eurasian-distributed species, so that admixture with them cannot have taken place in Africa.

The finding that Africans don't vary in their Neandertal admixture suggests that the source cannot have been an unknown African hominin related of Neandertals (in which case we'd expect to see variation in Africans). I don't know of any anthropologically plausible African cousin of the Neandertals, but, of course, the lack of anthropological evidence does not mean non-existence (cf. Denisovans as an anthropologically invisible Neandertal relative in Eurasia).

Genome Biol Evol. 2013 Oct 25. [Epub ahead of print]

Apparent Variation in Neanderthal Admixture among African Populations is Consistent with Gene Flow from non-African Populations.

Wang S, Lachance J, Tishkoff S, Hey J, Xing J.

Abstract

Recent studies have found evidence of introgression from Neanderthals into modern humans outside of sub-Saharan Africa. Given the geographic range of Neanderthals, the findings have been interpreted as evidence of gene exchange between Neanderthals and the modern humans descended from the Out-of-Africa (OOA) migration. Here we examine an alternative interpretation in which the introgression occurred earlier within Africa, between ancestors or relatives of Neanderthals and a subset of African modern humans who were the ancestors of those involved in the OOA migration. Under the alternative model, if the population structure among present-day Africans predates the OOA migration, we might find some African populations show a signal of Neanderthal introgression while others do not. To test this alternative model we compiled a whole-genome data set including 38 sub-Saharan Africans from eight populations and 25 non-African individuals from five populations. We assessed differences in the amount of Neanderthal-like SNP alleles among these populations and observed up to 1.5% difference in the number of Neanderthal-like alleles among African populations. Further analyses suggest that these differences are likely due to recent non-African admixture in these populations. After accounting for recent non-African admixture, our results do not support the alternative model of older (e.g., >100 kya) admixture between modern human and Neanderthal-like hominid within Africa.

Link

Interesting talks @ Penn: Zheng He and Mount Vesuvius

I had recently mentioned Zheng He on account of his Y chromosome.

Great Voyages: Zheng He


Pompeii Lecture Series: Mount Vesuvius in Human History

Long live the 28th October 1940