Non random mating

A new study published in PNAS finds evidence for non-random mating

Spouses are more genetically similar than two individuals chosen at random … our unadjusted GAM result of 0.045 suggests that a 1-SD increase in genetic similarity increases the probability of marriage by roughly 15%. This association is confounded, in part, by intraethnic marriage among whites but we continue to observe GAM even after a se- ries of models designed to eliminate this source of assortative mating.

This comes somewhat unexpected. Unfortunately, the authors missed in their discussion what Carole Ober published about HLA and mate choice in humans

Hutterite mate choice is influenced by HLA haplotypes, with an avoidance of spouses with haplotypes that are the same as one’s own.

So I am a bit confused – more similar in general but still different at the HLA locus??
Reminds me to the old joke, that your male genome is more similar to a male chimpanzee (on a per base statistic) than to your wife.