Microcomplement fixation studies on the evolution of alpha-glycerophosphate dehydrogenase within the genus Drosophila.

Abstract

Antisera were prepared against purified .alpha.-glycerophosphate dehydrogenase (EC 1.1.1.8) (.alpha.GPDH) from D. melanogaster, D. virilis and D. busckii. The immunological distances between the enzymes from the 3 spp. and those from 31 additional drosophilid species agree in general with the accepted phylogeny of the genus. These data permit an estimate that the subgenus Sophophora diverged 52 million yr ago from the line leading to the subgenus Drosophila. The antiserum against D. melanogaster .alpha.GPDH was capable of distinguishing allelic variants of .alpha.GPDH. On the basis of presumed single amino acid substitutions, no drosophilid .alpha.GPDH tested differed from the D. melanogaster enzyme by more than 8 or 9 substitutions. The study was extended to include representatives of 6 other dipteran families [Phoridae, Sarcophagidae, Muscidae, Tephritidae, Agromyzidae and Ephydridae]. The immunological distances between .alpha.GPDH from Drosophila and .alpha.GPDH from these dipterans were reasonably consistent with a phylogeny of the order Diptera established by more conventional means. The unit evolutionary period of this enzyme was estimated to be 18 million yr.