Constraints on the evolution of attractive traits: genetic (co)variance of zebra finch bill colour.
We estimated the heritability and genetic correlation between male and female bill colour in a laboratory population of zebra finches (Taeniopygia guttata) in order to examine the potential genetic constraints on the evolution of a sexually dimorphic trait. The heritability estimates of bill colour from regressions of offspring on single parents ranged from h2 = 0.34 to 0.73 and all but one of these estimates were significantly greater than zero. The restricted maximum likelihood heritability estimates for full- and half-siblings were significant for females (h2 = 0.48) but not significant for males (h2 = 0.45). The maximum likelihood estimates indicate that there is little dominance genetic variance for bill colour. The large genetic correlation between male and female bill colour (rg = 0.91) combined with opposing selection on male and female bill colour indicates that the evolution to sex-specific optima may proceed very slowly.
Price
D K
DK
Department of Ecology, Ethology, and Evolution, University of Illinois, Urbana 61801.
Burley
N T
NT
D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000235:genetics*; D003116:Color; D005260:Female; D014644:Genetic Variation; D008297:Male; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D012727:Sex Characteristics