quote:Soqotra, an island situated at the mouth of the Gulf of Aden in the northwest Indian Ocean between Africa and Arabia, is home to ~60,000 people subsisting through fishing and semi-nomadic pastoralism who speak a Modern South Arabian language. Most of what is known about Soqotri history derives from writings of foreign travellers who provided little detail about local people, and the geographic origins and genetic affinities of early Soqotri people has not yet been investigated directly. Here we report genome-wide data from 39 individuals who lived between ~650 and 1750 ce at six locations across the island and document strong genetic connections between Soqotra and the similarly isolated Hadramawt region of coastal South Arabia that likely reflects a source for the peopling of Soqotra. Medieval Soqotri can be modelled as deriving ~86% of their ancestry from a population such as that found in the Hadramawt today, with the remaining ~14% best proxied by an Iranian-related source with up to 2% ancestry from the Indian sub-continent, possibly reflecting genetic exchanges that occurred along with archaeologically documented trade from these regions. In contrast to all other genotyped populations of the Arabian Peninsula, genome-level analysis of the medieval Soqotri is consistent with no sub-Saharan African admixture dating to the Holocene. The deep ancestry of people from medieval Soqotra and the Hadramawt is also unique in deriving less from early Holocene Levantine farmers and more from groups such as Late Pleistocene hunter–gatherers from the Levant (Natufians) than other mainland Arabians. This attests to migrations by early farmers having less impact in southernmost Arabia and Soqotra and provides compelling evidence that there has not been complete population replacement between the Pleistocene and Holocene throughout the Arabian Peninsula. Medieval Soqotra harboured a small population that showed qualitatively different marriage practices from modern Soqotri, with first-cousin unions occurring significantly less frequently than today.
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Anyone else think the reported lack of SSA ancestry in these medieval samples (apart from one mtDNA) is a little weird? Socotra is awfully close to the Horn, after all.
Consistent with a founder effect and consanguineous unions, there is low diversity in Y chromosome haplogroups among medieval Soqotri males: all except one belong to J2-M172 and specifically to the same branch of J2b-Z534 (outlier I21109 belongs to J1a2a1a2d2b-Z2324). The near ubiquity of J2 haplogroups and paucity of J1 lineages is distinct from most of present-day mainland Yemen, where J1-M267 haplogroups dominate
This is consistent with the differences in the population history between Soqotra and most of the Arabian Peninsula that we identify through deep ancestry modelling
...
With mitochondrial DNA (mtDNA), we find the only evidence for African ancestry in medieval Soqotra. Specifically, we identify one individual belonging to African-associated haplogroup L3h2, today distributed primarily within northern parts of East Africa and Soqotra all other medieval Soqotri belong to the Eurasian-associated N and R branches of the mtDNA phylogeny (Supplementary Data 2), attesting to the strong Eurasian genetic connection that is also detected in mtDNA data from present-day people
Published: 23 March 2021 Origin and diffusion of human Y chromosome haplogroup J1-M267 Hovhannes Sahakyan
Y chromosome haplogroup J-M304 represents the major male lineage in West Asia today8,9,10,11,12. The 12f2a13 deletion and single nucleotide polymorphic (SNP) biallelic markers M3049 and P20914 define and characterize this haplogroup. It splits off from haplogroup IJ-M429 at ~ 45 thousand years ago (kya), while the time to the most recent common ancestor (TMRCA) of haplogroup J-M304 lineages is ~ 33 kya15,16. Studies associate haplogroup J-M304 with the spread of farming from the Near East to Europe11,17,18. Around the time of the Neolithic demographic transition3, the genome-wide ancestry of West Asian populations was geographically structured into three groups19,20,21,22. Among them, haplogroup J-M304 is found in the Caucasus/Iranian and Anatolian hunter-gatherers and farmers, but not in the Levantine ones. Unfortunately, so far aDNA studies are missing from the Arabian Peninsula and Mesopotamia, where haplogroup J-M304 is frequent nowadays. This haplogroup splits into J1-M267 and J2-M1729,11. While haplogroup J2-M172 is associated more with agriculture in the northern latitudes of West Asia, haplogroup J1-M267 has been connected with the spread of the pastoral economies in the West Asian arid zones 23, 24
23 Chiaroni, J. et al. The emergence of Y-chromosome haplogroup J1e among Arabic-speaking populations. Eur. J. Hum. Genet. 18, 348–353 (2010).Return to ref 23 in article Article PubMed Google Scholar
24 Chiaroni, J., King, R. J. & Underhill, P. A. Correlation of annual precipitation with human Y-chromosome diversity and the emergence of Neolithic agricultural and pastoral economies in the Fertile Crescent. Antiquity 82, 281–289 (2008).
wiki
History of Socatra
Written sources
In the late 2nd century BCE, Agatharchides recorded merchants from Potana, coming to the "Blessed Islands" (Socotra) to trade with Alexandrian merchants.[10]
The Periplus of the Erythraean Sea, a first-century CE Greek navigation aid describes Socotra as follows:
The inhabitants, few in number, live on one side of the island, that to the north, the part facing the mainland; they are settlers, a mixture of Arabs and Indians and even some Greeks, who sail out of there to trade.
— Periplus of the Erythraean Sea, §30[11] [The island was] subject to the King of the frankincense-bearing land [i.e. the Kingdom of Hadhramaut].
— Periplus of the Erythraean Sea, §31[12] The Weilüe, a Chinese historical text written in the third century CE states:
The king of Zesan (Socotra) is subject to Da Qin (Rome). His seat of government is in the middle of the sea… [Zesan] is in close communication with Angu city (Gerrha) in Anxi (Parthia).
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Petroglyph sites
Eriosh Petroglyphs The Eriosh Petroglyphs, located on the north coast 20 km south-west of the capital Hadibu, contain petroglyphs depicting figures of men, camels, foot symbology and crosses of uncertain dating.[14][15] In the outskirts of Suq 2.5 km west of Hadibu there is a petroglyph site containing cruciform shaped, plant-like, and foot symbology.[14] Hoq Cave, situated on the north-eastern coast of the island, contains a large number of inscriptions, drawings and archaeological objects.[14] Investigation showed that these had been left by sailors who visited the island between the first century BCE and the sixth century CE. Texts are written in Indian Brāhmī, South Arabian, Ethiopic, Greek, Palmyrene and Bactrian scripts and languages. This corpus of nearly 250 texts and drawings constitutes one of the main sources for the investigation of Indian Ocean trade networks in that time period,[16] indicating the diverse origins of those who used Socotra as a trading base in antiquity.[17] The Dahaisi Cave, located in the eastern interior of the island on the Momi Plateau, contains pictograms of cruciform and geometric patterns, Arabic inscriptions as well as zoomorphic figures attributed to between the first century BCE and the fifteen century CE.
quote:Originally posted by BrandonP: Anyone else think the reported lack of SSA ancestry in these medieval samples (apart from one mtDNA) is a little weird? Socotra is awfully close to the Horn, after all.
They have SSA-like ancestry embedded within there Natufian and Iranian ancestry, probably a tiny amount via there Anatolian related ancestry too. Also Horn Africans are significantly Eurasian related themselves, the core of the Axumite empire which was at times pretty involved in Yemeni affairs, even to the point of conquest on at least 2 occasions, was the highlands of Tigray Ethiopia and Eritrea, peoples in those regions today are roughly 50-60% Eurasian, so it would take a significant amount of Horn African ancestry to really increase there SSA levels.
Look at the sample labelled “Yemeni”, they score significant amounts of Mota compared to the soqotri.
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quote:Originally posted by BrandonP: Anyone else think the reported lack of SSA ancestry in these medieval samples (apart from one mtDNA) is a little weird? Socotra is awfully close to the Horn, after all.
They have SSA-like ancestry embedded within there Natufian and Iranian ancestry, probably a tiny amount via there Anatolian related ancestry too. Also Horn Africans are significantly Eurasian related themselves, the core of the Axumite empire which was at times pretty involved in Yemeni affairs, even to the point of conquest on at least 2 occasions, was the highlands of Tigray Ethiopia and Eritrea, peoples in those regions today are roughly 50-60% Eurasian, so it would take a significant amount of Horn African ancestry to really increase there SSA levels.
Look at the sample labelled “Yemeni”, they score significant amounts of Mota compared to the soqotri.
Understood, but I'd still expect the SSA to be non-zero if there were some people from the Horn intermingling with these Soqotri. Even the sampled Abusir el-Meleq mummies had a small amount of SSA.
quote:Originally posted by BrandonP: Anyone else think the reported lack of SSA ancestry in these medieval samples (apart from one mtDNA) is a little weird? Socotra is awfully close to the Horn, after all.
Reminds me of the findings for Bronze Age Cretans showing no African (not even North African ancestry) despite being close to North Africa. But I agree with SlimJim that there very well could be African ancestry embedded within the Eurasian ancestries. Neolithic Iranian for example has 'Basal Eurasian'. Also these are Medieval samples alone. Scholars say the island was inhabited since the Bronze Age if not earlier. But like Crete it depends on the samples taken.
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posted
I'm actually a bit shocked at how poor this is as a comprehensive study. The diversity in methodology keeps decreasing with more samples particularly those with African proximity.
Are we to conclude that modern day Yemeni populations who never shown any SSA lost their noise level Indian(related) ancestry because of an increase in West African ancestry? And why would natufians be used as a sole contributor of African shifted ancestry... The Natufian samples are of low coverage, why didn't they shift the proxy with Dzudzuana, Turk_Pinarbasi, and Ifri_ouberrid? Why no individual runs instead of grouping the samples for every test.especially since we have clear evidence of an African Haplogroup with no "African ancestry."
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posted
^ And just to add on to what you say, I haven't even heard of any genetic samples from ancient Yemeni remains of which there are plenty. Arabia itself seems to be devoid of ancient genetic studies with huge gaps in ancient human remains due to desert areas (Rubʿ al-Khali for one) that were once populated during the wet Holocene period. So I find it difficult to give an accurate assessment on Socotra without first having proper analyses of ancient Arabian samples.
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quote:Are we to conclude that modern day Yemeni populations who never shown any SSA lost their noise level Indian(related) ancestry because of an increase in West African ancestry? And why would natufians be used as a sole contributor of African shifted ancestry... The Natufian samples are of low coverage, why didn't they shift the proxy with Dzudzuana, Turk_Pinarbasi, and Ifri_ouberrid? Why no individual runs instead of grouping the samples for every test.especially since we have clear evidence of an African Haplogroup with no "African ancestry."
Do you think the results would look different if those other samples (e.g. Dzudzuana) were used instead of Natufians for the comparisons? And what do you think a better-assembled study on these Soqotri remains would look like overall?
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^ I don't know but remember that in the 2018 Loosdrecht et al. study modern Yemeni are intermediate between Taforalt and Afar East Africans on hand but North Africans on another.
Compare with the 2017 Schuenemann et al. (Abusir) study.
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