Vitellogenin protein diversity in the Hawaiian Drosophila

Egg and female hemolymph proteins were resolved via SDS-polyacrylamide gel electrophoresis in a diverse array of 33 endemic Hawaiian drosophilids, encompassing 17 picture-winged species, 3 of the antopocerus species group, 9 fungus feeders, 1 species from each of the modified mouthparts, crassifemur and ciliated tarsus groups, and 1 Scaptomyza species. Molecular weights of the two (10 species) or three vitellogenin bands (22 species) were highly variable, spanning a 7-kD range. The largest vitellogenin, V1, was the most variable, showing a change of some 10% in its mean size of 47.6 kD. The smallest V3 vitellogenin, mean size 44.1 kD, was evolutionarily the most conservative in size. The species Drosophila hawaiiensis was found to be polymorphic for two/three vitellogenin bands and, also, polymorphic with respect to the size of the V1 protein. No inter- or intrapopulation variability in vitellogenin size was detected in 10 other species examined. The major features of vitellogenin protein evolution in the Hawaiian Drosophila are change in molecular weight and regulatory differences that result in quantitative differences between species in patterns of vitellogenin protein production.