Balto-Slavs and Sarmatians in the Battle of Himera

G25 coordinates for most of the samples from the recent Reitsema et al. paper are available in a text file here. They're also in the G25 datasheets at the usual link here.

A basic distance analysis with the G25 data at Vahaduo shows that the two samples labeled Himera_480BCE_3 are either early Balts or Slavs. I suspect that they're Slavs, because I believe that early Slavs had this type of Baltic-like genetic structure before mixing with their non-Slavic-speaking neighbors. Well, that's my pet theory for now, so take it or leave it.

Distance to: ITA_Sicily_Himera_480BCE_3:I10943
0.03393838 HUN_IA_La_Tene_o:I18226
0.03572886 DEU_MA_Krakauer_Berg:KRA001
0.03618075 RUS_Pskov_VA:VK159
0.03899963 SWE_Gotland_VA:VK463
0.03915018 Baltic_EST_IA:s19_V12_1

Distance to: ITA_Sicily_Himera_480BCE_3:I10949
0.03573636 HUN_IA_La_Tene_o3:I25524
0.03698768 HUN_IA_La_Tene_o:I18226
0.03732752 SWE_Skara_VA:VK397
0.03767022 Baltic_EST_IA:s19_V12_1
0.03772687 DEU_MA_Krakauer_Berg:KRA001

On the other hand, I'm almost certain that the two Himera_480BCE_4 samples are Sarmatians. The good old G25 does it again!

Distance to: ITA_Sicily_Himera_480BCE_4:I10944
0.03100861 KAZ_Segizsay_Sarmatian:SGZ002
0.03548059 MDA_Sarmatian:I11925
0.03619219 RUS_Urals_Sarmatian:MJ56
0.03626538 RUS_Urals_Sarmatian:chy001
0.03904260 RUS_Urals_Sarmatian:MJ41

Distance to: ITA_Sicily_Himera_480BCE_4:I10947
0.02989458 RUS_Urals_Sarmatian:MJ43
0.03052790 RUS_Urals_Sarmatian:chy002
0.03170622 KAZ_Kangju:DA226
0.03288789 TUR_BlackSea_Samsun_Anc_C:I4529
0.03310149 KAZ_Aigyrly_Sarmatian:AIG003

See also...

Slavic-like Medieval Germans

Recent gene flow from Africa and the Near East into Europe

A new paper at PNAS by Botigué et al. takes a close look at African and Near Eastern admixture in Europe:

Human genetic diversity in southern Europe is higher than in other regions of the continent. This difference has been attributed to postglacial expansions, the demic diffusion of agriculture from the Near East, and gene flow from Africa. Using SNP data from 2,099 individuals in 43 populations, we show that estimates of recent shared ancestry between Europe and Africa are substantially increased when gene flow from North Africans, rather than Sub-Saharan Africans, is considered. The gradient of North African ancestry accounts for previous observations of low levels of sharing with Sub-Saharan Africa and is independent of recent gene flow from the Near East. The source of genetic diversity in southern Europe has important biomedical implications; we find that most disease risk alleles from genome-wide association studies follow expected patterns of divergence between Europe and North Africa, with the principal exception of multiple sclerosis.

The term "recent" is used throughout the paper to describe the IBD results, but as far as I can see there's no mention of any dates. Based on the data in the very thorough Ralph and Coop European IBD study (see here), I'd say that segments of over 1.5cM represent gene flow from well within the past 5,000 years. If this assumption is correct, then the results certainly make a lot of sense. That's because there were well documented historical events that could account for the main outcomes in the figure below: a) low level IBD sharing between Sub-Saharan Africa and much of Southern Europe; b) inflated IBD sharing between North Africa and Southwestern Europe; and c) inflated IBD sharing between Southeastern Europe and the Near East.

I probably don't need to discus in detail what these events might have been. Suffice it to say that the Mediterranean Basin has seen several major empires which facilitated regular population movements between Southern Europe, North Africa and the Near East. This process included the slave trade, which was one of the main economic activities in the region for a couple thousand years.

It's important to note, however, that fastIBD doesn't specify the direction of gene flow. In other words, shared IBD segments can be the result of our ancestors either receiving or giving admixture, or gene flow from a third party. But as Botigué et al. point out, the North African samples which show the highest IBD sharing with Iberians are also those with the lowest European ancestry proportions in the ADMIXTURE analysis (see below). Therefore, it's unlikely that this shared IBD is of European origin in any significant degree.

Key: Canis - Canary Islands; And - Andalusia; Gal - Galicia; Bas - Basques; Spa - Spain; Por - Portugal; Fra - France; Ita - Italy; Tsi - Tuscany; Gre - Greece ; ItaJ - Italian Jews; AshJ - Ashkenazi Jews; Qat - Qatar; NMor - North Morocco; SMor - South Morocco; OccS - Saharawi; Alg - Algeria; Tun - Tunisia; Lib - Libya; Egy - Egypt; Yri - Yoruba from Nigeria; Mkk - Maasai from Kenya.


There's also a PCA in the supplementary PDF which further underlines that most of the IBD sharing between Europe and North Africa, as well as Qatar, is not of European origin, because it creates significant substructures within the European sample.

Unfortunately the Qataris are the only Near Eastern sample used in the study. Then again, if I was to pick a single ethnic group to represent the Near East in an IBD study like this, then Qataris would probably be near the top of the list. That's because they've been affected by population movements from other parts of the Arabian Peninsula and also Persia, but at the same time never experienced significant gene flow from Europe. More information about the genome-wide genetic ancestry of Qataris is available in this recent open-access paper by Omberg et al.

Botigué et al. also make some interesting comments about Jewish genetic ancestry in Europe. The quote below comes from the supplementary PDF.

Another possible hypothesis to explain the increased diversity in southern Europe is that an influx of Jewish ancestry had a heterogeneous effect on genetic diversity in Europe. However, in most European populations here, virtually no Jewish ancestry was detected. On average, 1% of Jewish ancestry is found in Tuscan HapMap population and Italian Swiss, as well as Greeks and Cypriots. This may reflect the higher sharing with Near Eastern populations in the Italian peninsula and southeastern Europe (Fig. 2C) or low levels of gene flow with the early Italian Jewish communities (6). Estimates from the IBD analysis are in agreement with ADMIXTURE estimates that the amount of sharing between these populations is extremely low (SI Appendix, Table S3). Specifically, results of IBD sharing between southwestern Europe and North Africa are two orders of magnitude greater than those found between the same region and Jews, the average WEA for southern Europe and North Africa is 203, while for southwestern Europe and European Jews is 1.3.

Reference...

LR Botigué*, BM Henn*, S Gravel, BK Maples, CR Gignoux, E Corona, G Atzmon, E Burns, H Ostrer, C Flores, J Bertranpetit, D Comas, CD Bustamante, Gene flow from North Africa contributes to differential human genetic diversity in Southern Europe, PNAS, published online before print June 3, 2013, doi: 10.1073/pnas.1306223110