9306633 Shaffer This proposal will derive a phylogeny for the major lineages of chelonians (turtles) using nucleotide sequence data from several mitochondrial genes. This phylogeny together with information on fossil dates for the divergence of various turtle lineages will be used to examine rates of molecular divergence in turtles, thus providing a test for the molecular clock hypothesis. Morphological character divergence also will be examined in light of the relationships depicted by the molecular phylogeny. %%% Since the pioneering efforts of Zukerkandl and Pauling (1965), an increasingly large group of biologists have been intrigued with molecular data as a source of phylogenetically informative characters and a means of providing an independent estimate of divergence times using a molecular clock. The research outlined in this proposal will contribute directly to these two major areas of interest by exploiting the living diversity of turtles and their superb fossil record. ***
