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The Genomic History of the Middle East
#1
Излязло е ново изследване на база пълен геном за население от Близкия Изток, предимно от Арабските страни. Що се отнася до хаплогрупите, арабите масово се тестват и комерсиално, та имаме някаква представа от дърветата на YFULL и FTDNA. За хаплогрупата J1, типична за арабите се смята, че е дошла първоначално от Иран през Месопотамия през Бронза.

The Genomic History of the Middle East
Abstract
The Middle East is an important region to understand human evolution and migrations, but is underrepresented in genetic studies. We generated and analysed 137 high-coverage physically-phased genome sequences from eight Middle Eastern populations using linked-read sequencing. We found no genetic traces of early expansions out-of-Africa in present-day populations, but find Arabians have elevated Basal Eurasian ancestry that dilutes their Neanderthal ancestry. A divergence in population size within the region starts before the Neolithic, when Levantines expanded while Arabians maintained small populations that could have derived ancestry from local epipaleolithic hunter-gatherers. All populations suffered a bottleneck overlapping the archaeologically-documented 4.2 kiloyear aridification of the area, while regional migrations increased genetic structure, and may have contributed to the spread of the Semitic languages. We identify new variants that show evidence of selection, some dating from the onset of the desert climate in the region. Our results thus provide detailed insights into the genomic and selective histories of the Middle East.


https://www.biorxiv.org/content/10.1101/...8.342816v1

Опитват се да намерят следи от предполагаемото първо разселване на хората от Африка, но се оказва, че всички не са по-стари от 50-60х.г. в унисон с другите Западноевразийци. Намерено и едно много тясно  "гърло на бутилка" отпреди 4.2 х. години, което се свързва със силно засушаване на района. Сред арабите има и доста голям черен Африкански примес в последните 2000 г. който е вероятно следа от арабската търговия на роби черни африканци.

Another contrast between the Levant and Arabia is the excess of African ancestry in
Arabian populations. We find that the closest source of African ancestry for most populations
in our dataset is Bantu Speakers from Kenya, in addition to contributions from Nilo-Saharan
speakers from Ethiopia specifically in the Saudi population. We estimate that African
admixture in the Middle East occurred within the last 2,000 years, with most populations
showing signals of admixture around 500-1,000 years ago (Figure S5 and Table S2).



These results collectively suggest that present-day Middle Eastern populations do not harbour any
significant traces from an earlier expansion out of Africa, and all descend from the same
population that expanded out of the continent ~50-60 kya.

...
In addition to the local ancestry from Epipaleolithic/Neolithic people, we find an ancestry
related to ancient Iranians that is ubiquitous today in all Middle Easterners (orange
component in Figure 1C; Table S1). Previous studies showed that this ancestry was not
present in the Levant during the Neolithic period, but appears in the Bronze Age where
~50% of the local ancestry was replaced by a population carrying ancient Iran-related
ancestry (Lazaridis et al., 2016). We explored whether this ancestry penetrated both the
Levant and Arabia at the same time, and found that admixture dates mostly followed a North
to South cline, with the oldest admixture occurring in the Levant region between 3,900 and
5,600 ya (Table S3), followed by admixture in Egypt (2,900-4,700 ya), East Africa (2,200-
3,300) and Arabia (2,000-3,800). These times overlap with the dates for the Bronze Age
origin and spread of Semitic languages in the Middle East and East Africa estimated from
lexical data (Kitchen et al., 2009; Figure S8).
This population potentially introduced the Y chromosome haplogroup J1 into the region (Chiaroni et al., 2010; Lazaridis et al., 2016). The majority of the J1 haplogroup chromosomes in our dataset coalesce around ~5.6 [95% CI,
4.8-6.5] kya, agreeing with a potential Bronze Age expansion; however, we do find rarer
earlier diverged lineages coalescing ~17 kya (Figure S9)

...
To investigate Neanderthal introgression in our dataset, we exploited the
accurate phasing of our samples and compared cross-coalescent rates with the high
coverage Vindija Neanderthal genome (Prüfer et al., 2017). All Middle Easterners showed an
archaic admixture signal at a time point similar to other Eurasians (Figure 3A).

...

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