Electrophoretic variation of supernatant malate dehydrogenase in marsupials

Starch gel electrophoresis of supernatant malate dehydrogenase (MDH A₂) was performed on erythrocyte samples from 505 individual animals representative of 33 marsupial species. Most species exhibited electrophoretically identical forms of MDH A₂ activity with the exception of the grey kangaroos, Trichosurus possums, and bandicoots, thus confirming the phylogenetic relatedness of animals within each group and the conservative nature of this enzyme. Polymorphisms were observed in two of the six species analyzed whose mobilities were non-standard. Allelic isozyme patterns and those from interspecies F₁ hybrids between grey kangaroos and other macropods were consistent with a dimeric subunit structure and an autosomal locus (MDH-A) encoding the enzyme.