Meaning of disassortative mating

dis•as•sort'a•tive mat'ing

Pronunciation: (dis"u-sôr'tu-tiv), [key]
— Animal Behav., Psychol. Animal Behav.,Psychol.
  1. the reproductive pairing of individuals that have traits more dissimilar than would likely be the case if mating were random (contrasted with assortative mating). Cf. panmixia.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.