Two, "genetic ancestry" does not mean genes. You do not understand what they looked at. The markers are not genes.
And, although I quoted from the article, I also quoted from the study itself--which you, of course, ignored ("self-reported population ancestry likely provides a suitable proxy for genetic ancestry").
But never-you-mind: keep denying reality and recite the mantra: "blank slate, all environment, no genetic difference between groups or individuals that's meaningful, etc. etc."