Mitochondrial DNA structure in the Arabian Peninsula

Mitochondrial DNA structure in the Arabian Peninsula

Background
Two potential migratory routes followed by modern humans to colonize Eurasia from Africa have been proposed. These are the two natural passageways that connect both continents: the northern route through the Sinai Peninsula and the southern route across the Bab al Mandab strait. Recent archaeological and genetic evidence have favored a unique southern coastal route. Under this scenario, the study of the population genetic structure of the Arabian Peninsula, the first step out of Africa, to search for primary genetic links between Africa and Eurasia, is crucial. The haploid and maternally inherited mitochondrial DNA (mtDNA) molecule has been the most used genetic marker to identify and to relate lineages with clear geographic origins, as the African Ls and the Eurasian M and N that have a common root with the Africans L3.

Results
To assess the role of the Arabian Peninsula in the southern route, we genetically analyzed 553 Saudi Arabs using partial (546) and complete mtDNA (7) sequencing, and compared the lineages obtained with those present in Africa, the Near East, central, east and southeast Asia and Australasia. The results showed that the Arabian Peninsula has received substantial gene flow from Africa (20%), detected by the presence of L, M1 and U6 lineages; that an 18% of the Arabian Peninsula lineages have a clear eastern provenance, mainly represented by U lineages; but also by Indian M lineages and rare M links with Central Asia, Indonesia and even Australia. However, the bulk (62%) of the Arabian lineages has a Northern source.

Conclusion
Although there is evidence of Neolithic and more recent expansions in the Arabian Peninsula, mainly detected by (preHV)1 and J1b lineages, the lack of primitive autochthonous M and N sequences, suggests that this area has been more a receptor of human migrations, including historic ones, from Africa, India, Indonesia and even Australia, than a demographic expansion center along the proposed southern coastal

Odd that the authors refer to M1 as African, as they themselves point out it’s Eurasian in origin in another paper. However, they do radiate out of North Africa, so possibly that was what it meant.. see below.

m1-dist2

I’m guessing that a lot of the M1’s you find across North Africa and the near East were brought up from upper Egypt with the expansion of the Halfan culture into the Levant and Maghreb, and got into Ethiopia via the Southern expansion of the same population, following the M78 Y chromosome. Although I expect quite a few in the near East were due to the slave trade on the East African coast too. This paper also describes M1b as North African, not Ethiopian (although they haven’t standardised the naming yet, so M1b is differently named in various papers).

 

Also interesting was the appearance of some ‘Australian’ Mt DNA.

 However, the link found between the M Saudi 201 sequence and an M14 Australian sequence is puzzling. Although at first sight it could be taken as a signal of the connection between the two utmost ends of the southern route, it seems not to be the case. First, both lineages share three basal positions and this hypothetical link would considerably delay the arrival age of M in comparison to that of East Asia. It would be improbable that similar Australian links with other M lineages mainly from India were not found. Third, if the Arab lineage had such an old implantation in the Arabian Peninsula some detectable autochthonous radiation should be expected. Most probably, the M42 sequence belongs to an Australian clade and its related lineage found in Saudi Arabia is also of Australian origin. Historical links as those invoked to explain the presence of Indian and Indonesian sequences in the Arabian Peninsula pool should also be valid for this case. In our opinion, the camel trade between Saudi Arabia and Australia [54] could be a probable historic cause of this link. Future detection in Aboriginal Australians of other M42 lineages will confirm the Australian origin of this clade and its radiation age in that Continent. However, the link between the East Asia M10 clade [40] and the Australian M42 clade, if not due to convergence, seems to be more interesting as it would confirm, once more, the rapid expansion of macrohaplogroup M all along the Asian coasts [6,13]. The lack of autochthonous M and N lineages in the present day Arabian Peninsula populations confirms that this area was not a place of demographic expansion in the dispersal out of Africa [55].

 

6 responses to “Mitochondrial DNA structure in the Arabian Peninsula

  1. I doubt that this will be the end of the ‘southern route’ claims. The idea seems to be as deeply ingrained as once was the idea ‘we’re all descended from Adam and Eve in the garden of Eden’.

    “Most probably, the M42 sequence belongs to an Australian clade and its related lineage found in Saudi Arabia is also of Australian origin”.

    I’m pretty sure it was on this blog I mentioned the possibility that humans had expanded from around the South China Sea once they’d developed improved boats. I’m not quite ready to rest my case but this goes some way towards offering supporting evidence.

  2. I read the paper some time ago and found it also very interesting, though sadly limited to Saudia (another paper on Yemen, presumably even more interesting is pay-per-view, so I have not read it).

    A curious thing is that Aboriginal Australian clade (not fully well identified, if I read the paper corectly) is centered in the Hedjaz area (Western Arabia, near the Red Sea) and not in the South. I suspect that the “Australian” clade, with further research, could prove to be direct evidence for the coastal migration model (broadly speaking and specially for haplogroup M), now the whole reality could actually be much more complex than just a matter of coasts, with people probably using inland routes as well, specially when the deserts were in contraction.

    I think it’s near impossible in any case that Australian Aboriginals would have influenced Arabia in such a big manner (we are not talking of a mere erratic here). Whatever Terry says, canoing directly from Australia into Arabia is beyond the logical possibilities. It could be argued that the haplogroup could have been introduced via Indonesia (I think the paper does that) but I see a too large presence of this clade to be explained by such event, moreso when no SE Asian clades are found.

    For me the most probable explanation is that it’s a remnant of the OOA migration and that it will be shown eventually to be distinct from the Australian haplogroup.

  3. There is project ongoing with Eastern Biotech for collecting maximum information about Arabic population history through Y STR DNA test. Soon dnaancestry will have database in arabic language.

  4. Choosetobefree

    it will be hard to acheive this. you need to see it as events happening over time. But before the time we are in now (after the flood) there was a time before where we reached a point of highier social living where we traded and travelled. and most lickely 2 times before that, till a disarster set us right back, which will accour again in time and has been told through storys in over time. some how modern religion has turned these storys which warn and guide us into a religion that controls you, ashame really.

    I always read that the first intelligent ape/monkeys that evolved came from africa. Is this to say that this did not happen anywhere else?

    And if it did and africans left there in quiet primtive form and entered europe… like wise other primitive humans started travel bump into eacother steal there women and stock.

    anyone heard of fused dna we have. cant remember to much about would like to know more? if so is this natraul?

  5. analyzed 553 Saudi Arabs using partial (546) and complete mtDNA (7) sequencing!

    From which part of Saudi Arabia?

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