The proposed study will provide the first comprehensive analysis of evolutionary relationships in the genus Ambystoma, the mole salamanders. Relationships will be determined by measuring genetic differences in mitochondrial DNA. With a well supported phylogenetic tree, one can study the biogeographical factors involved in the adaptive radiation of the group. This part of the study will also provide information on the mechanisms of evolution of mitochondrial DNA in amphibians, a group for which to be used in this study may prove useful for determining genetic relationships in many other biological systems. A good phylogeny will provide the context for the second part of this study. The mole salamander genus includes several distinctive clonally reproducing (unisexual) forms; these originated by hybridization between different species of Ambystoma. In the second part of the proposed study, mitochondrial DNA will be used to analyze genetic variation in the clonal populations. This will provide information on the maternal ancestors of clonal forms. It will also show whether there were many or few such origins, recent or ancient. One will therefore be able to reconstruct a history of these lineages-- where did they come from, how, when, and to what extent did they spread. Such an evolutionary history will provide the necessary background for more detailed studies of the genetic mechanisms involved in producing clonal organisms.
