9419617 Springer Evolutionary relationships among orders and families of marsupials (eg. koalas, kangaroos, opossums) have been studied by paleontologists, anatomists, physiologists and biochemists. However, a number of questions remain answered including relationships between Australian and American taxa. Proposed for study are DNA sequences from two mitochondrial genes that code for ribosomal RNAs. The study will evaluate the usefulness of molecular vs. anatomical data in deciphering evolutionary relationships. Molecular data will also be used to estimate divergence times among marsupial lineages. These divergence times will be evaluated in the context of what is known about sea level change and the movement of continental plates in the geologic past to develop a zoogeographic hypothesis for the early evolution of marsupials. The database of DNA sequences generated in this study, in conjunction with sequences that are already available for placental mammals (eg. rodents, primates, whales, seals) , will allow for detailed study of the evolution of ribosomal RNA genes in mammals.
