When we talk about genetic variation between populations, most of the time we're referring to SNPs or other "simple" polymorphisms, mostly because that's what we have data on. Detailed population genetics studies of copy number variants are just starting to appear; this paper is one of them. It's an anlysis of the frequency of a deletion of the gene APOBEC3B, involved in immunity to retroviral infection. As you can see in the map below, the gene is present in most people of European and African descent, but is missing in a significant fraction of Asian and Native American populations. Nothing revolutionary here, but expect more studies of this sort in the future.

ADDENDUM: I hasten to add, lest RPM read this post, that when I say these studies are starting to appear, I'm speaking about these sorts of studies in humans. In Drosophila, large deletions and inversions are the classic genetic polymorphisms used in population genetic analyses (due to their easy visibility in polytene chromosomes).

Labels: Population genetics