Saturday, February 10, 2018

New Baltic samples on PCA plots

I have made two PCA plots using new Baltic samples published by Mittnik et al. 2018, but as far as I can see with a different approach.  On my plots modern populations are placed at first hand on grounds of ancient samples, giving, in my humble opinion, a historically correct approach.  I have also standardized  sample sizes of modern populations to minimize the effects of modern genetic drift, which of course, if exists, will lead to comparison error due to irrelevant PCA-components.  Thirdly I have here two regional view; Eurasian and European.  The Asian effect on the Eurasian picture is pronounced in certain modern populations implying Asian admixture events after the Bronze Age Europe.

Eurasian picture:

Close-up of Eurasian picture:

European picture:

edit 10.2.2018

On the Eurasian picture the first dimension (X) represents East-Asian and Siberian maximums and the second one (Y) represents ancient farmer maximum.  So the picture isn't relevant for checking dimensions inside present-day Europe.  It is easy to understand that the flat left represents Asian/Siberian minimum regardless of later European structures.  Similarly the the vertical axis represents variation between ancient farmers and hunter-gatherers rather than structures inside present-day Europe.   The third picture (Europeans only) represents historically correct variation between ancient farmers and hunter-gatherers and exclusively to these variations ancient Steppe populations.  

Wednesday, February 7, 2018

New Baltic samples in comparison to present-day populations

A large amount of new ancient samples are published by Mittnik et al 2018.
I compared those samples against modern local populations using F3-statistics (qp3Pop) using Chimp as the outgroup to eliminate even smallest impact of African/Near Eastern gene flow after the OOA event.   F3-scores were divided by a constant value giving results below 10.