sunnuntai 25. tammikuuta 2015

Later Middle-Eastern and Native American like admixtures in Europe

I made new MixMapper tests, now using only high quality ancient samples, Loschbour, BR2, LBK380, NE1 and Kostenki.   Definitely this is not most informative, but shows less distort in qualifying farmer and hunter-gatherer groups.

The second table shows the probability of showing more Middle-Eastern admixture than those ancient farmers.  It is found by searching best admixture fits with mandatory Bedouin reference samples.  Negative alpha means no additional Middle-Eastern, positive alpha means a need for additional Bedouin-like Middle-Eastern admixture to create the best fit with ancient samples.   Please note that Basques show lowest resnorm (best fit) and still no additional Middle-Eastern making the best fit in the junction point LBK380-NE1.

My last table shows possible Karitiana-like admixture in a same way.   Note that  French, Bulgarian, Spanish, Sicilian, Greek and Turkish groups would very likely show negative Karitian with Loschbour, but the best fit is found with ancient farmer groups.  Basques show minimum admixture, again.

edit 26.01.15

Sardinians were forgotten accidentally.  They show no Karitiana-like admixture, but some Bedouin-like later admixture sure exists, more than among Basques.  

I received a question about the lack of all Middle-Eastern affinity among some North Europeans, which sounds the be wrong.  This test searched only Bedouin-like admixture, not Middle-Eastern in general.  It is a great idea to include more Middle-Easteners to find more coverage in Europe, but as far as I have understood the Bedouins are one of the purest local people there and probably represent unidirectional gene flow from the Middle East.   So the test arrangement is simple, but turns out to be much worse to interpret with a more complex Middle-Eastern data set.   This same applies also to Native American and Siberian admixtures. 

3 kommenttia:

  1. Very interesting.

    Is there a link somewhere that described how to interpret MixMapper tests? I'm a bit confused Is the one with Bedouin, testing if Europeans need extra middle eastern ancestry beyond being 50% Bedouin, and branch 3?

  2. Of course the Bedouin admix in Europe is very likely nonexistent. My goal was to search sure Middle-Eastern admixture which came after the branch 3 and try to avoid bidirectional gene flow effect that has been possible during thousands years. Earlier tests have shown that the Bedouins are purest living Middle-Easteners, but not all people in the Middle-East. Similarly I used Karitiana samples to avoid North European admixture among North Asians. But my goal is to make a test to find this kind of later admixtures from Asia and Middle-east to Europe in general. It however needs to have pure ancient genomes and we don't have them from the Middle-East. Unfortunately also ancient Asian samples has low quality.

  3. Although Karitianas and Bedouins can't have significant European admixture they sure have East Asian and African admixtures. However as a difference signal to Europeans those admixes have smaller consequence, without denying East and North Asian admixtures in Northeast Europe and African admixture in southernmost Europe.


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