Population Biology of the psr Chromosome

近年来，人们越来越关注 一些遗传因素可能是“自私的”， “寄生”，即它们可能除了自己的功能之外没有其他功能 在一个物种中繁殖。 这里的研究最关注 已知的寄生元件的极端例子是PSR（父系 丽蝇蛹集丽蝇蛹集 Psr传输 正常情况下，但随后会导致父系染色体的丢失。 因为雄性通常是单倍体而雌性是二倍体 在昆虫中，psr的作用是将二倍体雌性卵转化为 单倍体雄性卵子（携带psr）通过完全破坏 父亲的基因组 Psr由此获得传输优势 表型，因为它具有通过男性和 通过女性传播。 这是一个很好的系统，用于研究 寄生遗传因子 将开展研究， 回答以下问题：（1）什么是 psr在自然种群中的分布(b)如何 人口结构影响psr频率？（c）什么是 psr染色体的起源 这些问题都可以回答 因为重组克隆可用于表征 染色体和人口研究。 此外，程序 为psr的群体遗传学研究建立了 实验室和现场。 遗传、细胞遗传和分子遗传 研究将确定psr染色体的结构。 实地研究将确定psr在北 美国黄蜂种群的3个密切相关的Nasonia物种。 实验室种群实验将检验PSR种群 不同种群结构下的动态 最后 psr染色体上序列的可能起源是 通过比较三种黄蜂的模式来确定。 除了提供对遗传学的基本见解， 进化的“自私“的DNA，psr染色体可能是一个 研究染色体遗传基础的一种易操作的系统 印记 Psr作为一种生物活性物质也有很大的潜力。 害虫防治剂。

Within recent years there has been increasing interest in the concept that some genetic elements may be "selfish" or "parasitic", i.e. they may have no function other than their own propagation within a species. Research here concerns the most extreme example of a parasitic element known, the psr (paternal sex ratio) chromosome in Nasonia vitripennis. Psr is transmitted normally, but then causes loss of the paternal chromosomes. Because males are normally haploid and females diploid in this insect, the effect of psr is to convert diploid female eggs into haploid male eggs (which carry psr) by totally destroying the paternal genome. Psr gains a transmission advantage from this phenotype because it has a high transmission through males and a poor transmission through females. This is an excellent system for studying the evolution of parasitic genetic elements. Research will be undertaken to answer the following specific questions, (a) What is the distribution of psr in natural populations?, (b) How does population structure affect frequency of psr? and (c) What is the origin of the psr chromosome? These questions can be answered because recombinant clones can be used to characterize the chromosome and for population studies. In addition, procedures are established for population genetic studies of psr in both the laboratory and field. Genetic, cytogenetic and molecular studies will determine the structure of the psr chromosome. Field studies will determine the distribution of psr in North American wasp populations of 3 closely related Nasonia species. Laboratory population experiments will examine psr population dynamics under different population structures. Finally the possible origin of sequences on the psr chromosome will be determined by comparing patterns in the 3 wasp species. Besides providing basic insight into the genetics and evolution of "selfish " DNA, the psr chromosome could be a tractable system for studying the genetic basis of chromosome imprinting. Psr also has significant potential as a biological control agent of pest insects.