Isopleths

Simranjit has done a great job of creating some maps showing the distribution of the various ancestral components at K=16. He has posted them on DNA Forums and sent them to me.

The gradation is from Dark green (low) to Dark red (high) for most of them.

Basically the percentages for each Component are divided into 32 equal intervals, to create the contour effect. Take note that it represents relative values not absolute.

Here is C1 South Asian:

C2 Balochistan/Caucasus:

C5 Southwest Asian:

C6 European:

C12 Siberian:

Great job, Simranjit!

14 Comments.

  1. The problem with such maps is that excluded populations have usually arbitrarily assigned colors/shades, so such maps are misleading for excluded populations. To give an example, Central Asian Turkic republics that were excluded from analysis appear much less Siberian on the map than they actually are.

    Another problem with such maps is that they usually ignore population sizes. Case in point, again from Central Asia, Uzbekistan appears much less Siberian on the map than it actually is because of the equal treatment of Uzbeks and Uzbekistani Jews. But in actuality, Jews have always been a very small minority in Uzbekistan, so they would have no visible effect on the map if the population of the communities were taken into account.

    • I would most likely need to exclude the diaspora jews (iranian , uzbek etc) . I included them because they were important in the C2 component map. They have elevated amounts of C2 as compared to their general population(eg. iranians compared to iranian jews).
      I also did not include all populations(africans were practically ignore, as well as most europeans).

      I might need to drop minorities for most analysis.

    • The excluded populations issue can be fixed by using chloropleths instead of isopleths, though then you won't see gradients, just regions with different shades/colors.

  2. These are very nice! There should be a way to represent the slope of the gradient as well. These charts imply a uniformly smooth gradient whereas quite a few of these have steep transitions between regions.

  3. Great graphs, really allows for great visualiation.

    C2 is basically a map of Greater Iran; it really is shocking.

    I'm happy with the name but just reminds me of a map of the Sassanian\Achaemanian empires.

    Please note in no way am I suggesting its a function of that, probably pre-dates these ancient empires by couple of millennia.

    • Actually the shocking thing is how off the charts this is for a Dravidian-speaking population, the Brahui. That is extremely intriguing because the standard story on the Brahuis is that they are a holdout from a period before Indo-Iranian languages engulfed the whole region. Assuming dilution of the original genetic stock (this is a dangerous assumption because languages and genes can travel pretty independently - indeed must have in order for both the purest C2s and the purest C1s to *both* be Dravidian speakers!) due to Indo-Iranian and other migrations into this area, this would linguistically argue that C2 is the component representing the original Dravidian/Elamite speakers - see http://en.wikipedia.org/wiki/Elamo-Dravidian_languages.

  4. I will be doing a south asian isopleth (including the peripheries like iran etc) using the project participants. For states where we have brahmins and non-brahmins , i will do them separately as the difference in certain components can be substantial, especially for the south. I will also include HDGP Ref1 K=12 populations (eg. pathan, balochi, makrani etc ).

    This one should be interesting.

  5. Harappa Participant Admixture Maps | Harappa Ancestry Project - pingback on March 18, 2011 at 9:44 am

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