The genus Tetrahymena is an important group of ciliate protozoans, possibly descended with little modification from the earliest eukaryotic organisms. Species of this genus are commonly used laboratory organisms. Dr. Clifford Brunk proposes to obtain the DNA sequences of the actin gene in 7 to 10 species of the genus, and to use these sequence data to reconstruct their ancestor-descendant relationships. This evolutionary framework will form the foundation for future studies of other gene sequences in these species. Rates of evolution in different genes can then be compared, leading to a better understanding of the mechanisms of molecular evolution. The sequences obtained can also be compared with those of other early eukaryotes to reveal their evolutionary relationships. The proposed research has implications beyond the narrow field of ciliate systematics. The research will illuminate the pattern of evolution in this early group, and will lead to a clearer picture of the radiation of eukaryotes. This project will lead to a better understanding of how genes replicate and evolve within a single lineage over long periods of time.
