Albumin evolution in polyploid species of the genusXenopus

Publisher Website
Google Scholar
Abstract
Electrophoresis of serum from 21Xenopus species and subspecies reveals variable numbers of albumin bands. The diploidX. tropicalis has one albumin, while the tetraploid species(laevis, borealis, muelleri, clivii, fraseri, epitropicalis) have two. The octoploid species(amieti, boumbaensis, wittei, vestitus, andrei) have two to three bands, and the dodecaploidX. ruwenzoriensis has three. The molecular weight of thexenopus albumins varies from 68 kd (in thetropicalis group) to 74 kd. The subspecies ofX. laevis possess two albumins of different molecular weights (70 and 74 kd), whereas most species have only 70-kd albumins. Peptide maps have been obtained from albumin electromorphs by limited proteolysis in sodium dodecyl sulfate (SDS) gels, usingS. aureus V8 protease. The peptide patterns produced by electromorphs from the same tetraploidXenopus species generally differ from each other, suggesting that the two albumin genes contain a substantial amount of structural differences. In addition, the peptide maps are diagnostic for most tetraploid species and for some subspecies ofX. laevis as well. Proteolysis of albumins from most octoploid and dodecaploid species results in patterns which are very similar to the ones produced by the electromorphs fromX. fraseri. The albumins ofX. vestitus differ from those of the other octoploid species.X. andrei possesses twofraseri-type and onevestitus-type albumin, which indicates that it probably originated by allopolyploidy.