Geographical patterns of genetic variability in introduced Australian populations of the marine toad, Bufo marinus: sorbitol dehydrogenase, Sdh.

AThe marine toad, Bufo marinus, was introduced to Australia from Hawaii in 1935. From 1935 to 1974, the toad population expanded exponentially to occupy 584,000 km(2), and now has a continuous distribution from Cape York to Tweed River on the eastern coast of the continent. Genetic analysis of the population indicates a difference in allele frequency at the sorbitol dehydrogenase locus. There are two alleles segregating at the locus (NAD-Sdha and NAD-Sdhb). the NAD-Sdhaa homozygote is common in the two southern populations. but uncommon in northern populations. The north-south difference has been established in less than 25 generations.