Female sticklebacks count alleles in a strategy of sexual selection explaining MHC polymorphism.
Reusch T B H, Häberli M A, Aeschlimann P B, Milinski M (2001); Nature, 414(6861):300-302, doi: 10.1038/35104547
Reusch T B H, Häberli M A, Aeschlimann P B, Milinski M (2001); Nature, 414(6861):300-302, doi: 10.1038/35104547