MOLECULAR AND EVOLUTIONARY GENETICS OF SEGREGATION

分离的分子和进化遗传学

基本信息

批准号：
3297178
负责人：
CHUNG-I WU
金额：
$ 12.46万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
1991
资助国家：
美国
起止时间：
1991-09-01 至 1994-03-31
项目状态：
已结题

项目摘要

Segregation Distorter (SD) of Drosophila melanogasteris one of the best studied meiotic drive systems at the chromosomal and population level. We are now ready to study the molecular basis of SD. Molecular cloning will also lead to a better understanding of the population genetics of this system. The target for segregation distortion is the Responder (Rsp) locus: the alleles at the locus are broadly classified as sensitive or insensitive. We have found that a tandem array of 100-1,000 repeats are in all eight sensitive chromosomes so far examined. The array of repeats are absent in all eight insensitive chromosomes examined. Seven copies of the repeats have been sequenced which represent a novel class of satellite DNA and its hypothetical roles in chromatin condensation and segregation. An aberrant process of condensation is a very likely cause of spermiogenic failure, resulting in segregation distortion. We propose to study three aspects of Rsp. I) Further molecular characterization to delineate the limit of the Rsp locus. We plan to use chromosomes of various construct, such as deletions, translocations free duplications as well as naturally-occurring variants, to achieve this goal. The sequences sufficient as well as necessary for sensitivity will be identified. Our data suggest such sequences are none other than the large array of repeats themselves and we will further test this hypothesis that sensitivity is a direct consequence of the size of the tandem array. Sequencing a larger number of repeats will be carried out for molecular evolution studies. II) Evolutionary and population genetic aspects of SD will be studied. We will characterize the structure of Rsp in closely related species. Rsp alleles in natural populations will be surveyed. Four experimental populations will be set up and monitored. These populations will represent competition between sensitive and insensitive chromosomes both in the presence and absence of SD chromosomes. A satellite amplification hypothesis, proposed to explain perplexing observations on SD, will be tested. III) Molecular mechanisms underlying distortion will be explored. We will investigate if the Rsp alleles are transcribed under distorting and nondistorting conditions. We have developed a long term plan to study the chromatin structure associated with the Rsp satellite DNA. Assays for proteins that bind to such DNA in cell lines and in different tissues are planned.

黑腹果蝇的分离扭曲者 (SD) 之一研究最深入的染色体减数分裂驱动系统人口水平。我们现在准备研究分子基础标清。分子克隆也将带来更好的理解该系统的群体遗传学。目标为分离扭曲是响应者 (Rsp) 基因座：位于的等位基因该基因座大致分为敏感或不敏感。我们发现总共有 100-1,000 个重复的串联阵列迄今为止检查了八条敏感染色体。的数组在所有八个检查的不敏感染色体中均不存在重复。七个重复拷贝已被测序，它们代表一类新型卫星 DNA 及其假设的作用染色质凝聚和分离。一个异常的过程冷凝很可能是精子发生失败的原因，导致偏析畸变。我们建议研究 Rsp 的三个方面。 I) 进一步的分子表征来描绘 Rsp 基因座的极限。我们计划使用各种构造的染色体，例如缺失，易位无重复以及自然发生变体，以实现这一目标。序列足够以及将确定敏感性所必需的。我们的数据表明这样序列就是大量的重复序列他们自己，我们将进一步检验这个假设灵敏度是串联尺寸的直接结果大批。将进行大量重复测序用于分子进化研究。 II）进化与人口将研究 SD 的遗传方面。我们将表征密切相关物种中 Rsp 的结构。天然的Rsp等位基因将对人口进行调查。四个实验群体将进行设置和监控。这些人口将代表敏感染色体和不敏感染色体之间的竞争存在和不存在 SD 染色体的情况下。一颗卫星放大假说，提出来解释令人困惑的问题对 SD 的观察结果将进行测试。 III) 分子机制将探讨潜在的扭曲。我们将调查是否 Rsp等位基因在扭曲和非扭曲下转录状况。我们制定了一项长期计划来研究与 Rsp 卫星 DNA 相关的染色质结构。在细胞系和体内与此类 DNA 结合的蛋白质的测定计划了不同的组织。