The Origins of Parasitism in Lice: Phylogenetics of Psocodea

寄生虱是一组以鸟类和哺乳动物的皮肤，羽毛和血液为食的昆虫。 这些昆虫被认为是从树皮虱的共同祖先进化而来的，树皮虱生活在树上，以地衣和真菌为食。 然而，最近来自DNA序列的证据表明，这群昆虫中可能至少有两种寄生起源。 拟议项目的目标是通过对160多种寄生虫和树皮虱进行测序，并使用各种方法重建进化树，使用来自细胞核和寄生虫的大量DNA序列来测试这一想法。 这些树将被用来重建在这群昆虫中出现了多少次寄生。 该项目还将通过制作所有已知寄生虱和树皮虱物种的物种网页（共10 000多个物种和网页），为教育工具做出贡献。 这些网页将在生命之树网络项目，其目标是有一个地球上所有生命的系统发育树，并有这个树显示在网络上。 一名研究生将接受关于这些群体分类的培训，并将为这些网页的内容作出贡献。 最后，通过了解寄生虫在各种生物中起源的频率，我们可以更多地了解宿主转换的可能性以及新寄生虫和疾病的起源可能在人类中，这是一个正在进行的问题，例如禽流感。

Parasitic lice are a group of insects that feed on the skin, feathers, and blood of birds and mammals. These insects are believed to have evolved from a common ancestor within the bark lice, which live on trees and feed on lichen and fungi. However, recent evidence from DNA sequences suggests that there might have been at least two origins of parasitism in this group of insects. The goal of the proposed project is to test this idea using a wide array of DNA sequences both from the nucleus and mitochondrion by sequencing over 160 species of parasitic and bark lice and reconstructing evolutionary trees using a variety of methods. These trees will be used to reconstruct how many times parasitism arose within this group of insects. This project will also contribute to educational tools by producing species web pages for all known species of parasitic lice and bark lice (over 10,000 species and web pages total). These pages will be within the Tree of Life web project, whose goal is to have a phylogenetic tree for all life on earth and have this tree displayed over the web. A graduate student will receive training on the systematics of these groups and will contribute to the content of these web pages. Finally, by understanding how often parasitism might originate in various organisms, we can understand more about how likely host switches and the origin of new parasites and diseases might be in humans, which is an ongoing question for diseases like bird flu.