Immunological Evolution of Albumin in the Estrildine Finches (Aves, Passeriformes) Is Far From Clock-Like

Abstract

On the basis of microcomplement fixation studies, the finch Taeniopygia guttata has an albumin whose immunological properties are very different from those of other finches. Outgroup analysis, microcomplement fixation of transferrin, and electrophoretic behaviour of finch albumin, together with phylogenetic considerations based upon chromosomes and allozymes, revealed that the difference is due to rapid change in the immunological properties of T. guttata albumin rather than to a distant relationship of T. guttata to other finches. Indeed, the immunological properties of the albumin of T. guttata has undergone about 15 times as much change as would be expected for an albumin clock. The results highlight the caution that should be exercised when applying the molecular clock ad hoc to immunological data.