Dissertation Research: Molecular Characterization and Population Biology of P Elements in Natural Populations of Drosophila

9701252 Kidwell转座因子（TE）存在于大多数生物体中，包括人类、苍蝇、植物和细菌，其中它们可以构成高达40%或更多的遗传物质。 尽管它们很丰富，但对TE如何进化知之甚少。 本项目旨在研究果蝇属果蝇中的一个TEs家族--P元件的进化。 TE是移动的DNA片段，可以自我复制并插入宿主物种的新染色体位点。 像病毒一样，它们也可以转移到新的宿主。将对两种果蝇的P元件DNA进行测序。 目的是：1）评估自然种群中P元件结构和序列的变异; 2）调查不同元件区域的核苷酸取代率，并评估这些比率揭示了选择性限制的存在; 3）估计果蝇物种之间P元件的转移率。 这项调查将有助于了解的过程，决定了进化和维护基因组中的TE随着时间的推移。 由于TE和病毒在宿主入侵能力和DNA结构方面具有相似性，这些结果将揭示病毒本身如何在其宿主生物体中维持和进化。

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.