9701252 Kidwell Transposable elements (TEs) are present in most organisms, including humans, flies, plants and bacteria, where they can constitute up to 40% or more of the genetic material. Despite their abundance, very little is known about how TEs evolve. This project is to study the evolution of P elements, a family of TEs found in fruitflies of the genus Drosophila. TEs are mobile DNA segments that can self-replicate and insert into new chromosomal sites of the host species. Like viruses, they can also transfer to new hosts. P element DNA of flies of two Drosophila species will be sequenced. The goals are 1) to assess variation in P element structure and sequence in natural populations; 2) to investigate nucleotide substitution rates in different element regions and to assess what those rates reveal about the presence of selective constraints; and 3) to estimate the rate of transfer of P elements between Drosophila species. This investigation will contribute to understanding the processes that determine the evolution and maintenance of TEs in genomes through time. Because TEs and viruses have similarities in host invasion capabilities and in DNA structure, these results will shed light on how viruses themselves are maintained and evolve in their host organisms.
