Rates of Albumin Evolution in Parrots (Aves, Psittaciformes)

Abstract

A number of lines of evidence suggest that the rate of molecular evolution in birds is slower than in other vertebrates. This hypothesis was tested by measuring the extent of amino-acid sequence divergence in albumin among species of parrots by means of microcomplement fixation. This group was chosen because its modern distribution is strongly suggestive of a Gondwanan origin. The results show that the intercontinental albumin distances are well below those expected for a Gondwanan group. These data are in accord with the hypothesis that birds have a slower rate of molecular evolution, although other explanations are possible.