Search Result for "disassortative mating":
Wordnet 3.0

NOUN (1)

1. mating of individuals having traits more dissimilar than likely in random mating; 



WordNet (r) 3.0 (2006):

disassortative mating
    n 1: mating of individuals having traits more dissimilar than
         likely in random mating [ant: assortative mating]