The division between "French" and "Italian" is simply too good to be true and cannot be representative of the entire population of both countries. Besides the obvious proximity, there has been extensive migration for centuries. Roughly half the native of Marseilles have Italian names, and a sizeable number of Italians have French as their first language in Piedmont.

If they excluded anyone with a foreign grandparent, well, they simply excluded 40% of all French people, which limits the applicability of the results for practical purposes.

I can't access the full paper now but I suspect that the samples were taken from geographically small zones within their respective countries.

In fact the relative small size of both clusters is also indicative of sample restriction (especially for France, which has a lot of variation). I hope that they didn't deliberately take the French sample from highly special region like Britanny, Alsace or Flanders.

/wild speculation ftw!

It seems that no one wants their study to be used to answer questions about racial differences in intelligence.

In fact the relative small size of both clusters is also indicative of sample restriction (especially for France, which has a lot of variation). I hope that they didn't deliberately take the French sample from highly special region like Britanny, Alsace or Flanders.

i thought the HGDP samples were collected a long time ago.

the french samples were obtained from multiple regions within france, although I can't find many details about precisely where these regions were. the "italian" samples were obtained from Bergamo, north-east of Milan (could be a population isolate, but seems unlikely).

http://www.cephb.fr/HGDP-CEPH-Pa...H_Table1- 1.html