MHC GENOTYPE AND MALE ORNAMENTATION - GENETIC-EVIDENCE FOR THE HAMILTON-ZUK MODEL

The major histocompatibility complex (MHC) is an immunologically impor tant cluster of highly variable genes that is known to affect fitness in domesticated mammals and birds. Spur length of male pheasants in so uthern Sweden correlates with male viability, female mate choice, and offspring survival rate. Here we show by genetic analyses that the MHC genotype is associated with variation in both male spur length and ma le viability. These are the first data that directly support a 'good g enes' hypothesis by Hamilton and Zuk predicting that females discrimin ate among males on the basis of secondary sexual characters in order t o pass on genes for disease resistance that improve fitness in their o ffspring.