MALE RECOMBINATION - MUTATOR SYSTEM IN DROSOPHILA

孟德尔1：1分离比已被许多理论所接受， 群体遗传学这个项目的长期目标是表明， “非孟德尔比率”实际上是一般规律。具体目标 项目是重新建立一个正式的遗传基础的元素， 黑腹果蝇中的分离畸变系统。SD系统 被认为是非孟德尔分离的最好例子之一 （减数分裂驱动）。对这一模型系统的研究将为我们提供一个很好的 实现上述长期目标的基础。几个模型有 有人提出来解释偏析变形的过程，但不是全部 到目前为止所作的观察可以令人满意地解释这些 模型在所有提出的模型中有一个共同的预测，即， 在Sd杂合子Rsp（不敏感）/Rsp（敏感）男性中， 携带Rsp（敏感）等位基因的染色体是扭曲的，但 染色体与Rsp（不敏感）是不是。然而，这一预测被 完全颠覆了我最近的一些观察我试探 称这种现象为负偏析畸变， 质疑最基本的敏感和不敏感的概念， Rsp等位基因。除了迄今为止可持续发展系统的四个基本要素外， 在这个系统中，一定还有几个起关键作用的人- 确定分离扭曲方向的作用（至少一个 在第二染色体和至少一个在X染色体中）。包括这些新 元素，我计划重新建立正式的遗传基础隔离 一次又一次的扭曲为了做到这一点，我将采用"人工授精 女性转移"实验计划，而不是采用 传统上使用的交配计划，其中只有一小部分的总后代 这样的结果将为我们提供一个更好的估计 “绝对值”，而不是“相对值”。结果进行 研究将要求我们重新评估许多群体遗传学， 对人类群体的预测，如由于暴露造成的遗传损害 辐射和化学物质的影响。

Mendelian 1:1 segregation ratio has been accepted in many theories in population genetics. The long-term goal of this project is to show that "non-Mendelian ratio" is in fact the general rule. Specific aim of this project is to re-establish a formal genetic basis of the elements of Segregation Distorter (SD) system in Drosophila melanogaster. The SD system has been known as one of the best examples of non-Mendelian segregation (meiotic drive). Studies on this model system will provide us with a good basis to approach the long-term goal described above. Several models have been proposed to explain the process of segregation distortion, but not all of the observations thus far made can be satisfactorily explained by those models. There is one common prediction among all the proposed models, i.e., in an Sd heterozygous Rsp (insensitive)/Rsp (sensitive) male, the chromosome carrying the Rsp (sensitive) allele is distorted, but the chromosome with the Rsp (insensitive) is not. However, this prediction was completely re-versed in some of my recent observations. I tentatively termed this phenomenon as negative segregation distortion and it appears to question the most basic concept of sensitivity and insensitivity of the Rsp alleles. Besides four basic elements of the SD system so far characterized, there must be several more in this system which play key- roles to determine the direction of segregation distortion (at least one in the second and at least one in the X chromosomes). Including these new elements, I plan to reestablish the formal genetic basis of segregation distortion once and for all. To do this, I will adopt the "inseminated female transfer" experimental scheme, instead of adopting the conventionally used mating scheme in which only a fraction of total progeny was sampled, such that the results will provide us with a better estimate of the "absolute values" but not of the "relative values". Results of these studies will require us to re-evaluate many of the population genetics predictions on human populations such as genetic damages due to exposure to irradiation and chemicals through generations.