A swarm of locusts?

The dam has truly broken. Below is my usual Principal Component Analysis (PCA) of ancient West Eurasian genetic variation, except now also featuring the new samples from Mathieson et al. 2018 and Olalde et al. 2018. Incredibly, there are almost a thousand ancient individuals on this plot. The relevant datasheet is available here.

My imagination is probably running wild from all of this excitement, and I apologize if it is, but I reckon that the “Post-Kurgan expansion Europe” cluster actually looks like it’s beginning to swarm all over “Old Europe”, much like a swarm of locusts. These are, of course, our Bronze Age ancestors, rich in steppe ancestry and Y-haplogroups R1a and R1b. I reserve judgment on whether that’s a good or bad thing.
In any case, note that I highlighted three samples in this analysis. The reason I did this is because I believe that at least two of them might be crucial to understating the Proto-Indo-European (PIE) expansion. I’ve given hints as to why on the plot. Am I on the right track? Feel free to let me know in the comments below.
See also…
Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…
Who’s your (proto) daddy Western Europeans?
Migration of the Bell Beakers—but not from Iberia (Olalde et al. 2018)

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