Evolution of Dimorphic Sex Chromosomes

二态性染色体的进化

• 批准号: 9118893
• 负责人: William Rice
• 金额: $ 4万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-03-15 至 1994-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9118893&HistoricalAwards=false
• 关键词: Evolution; Dimorphic; Sex; Chromosomes

The proposed research tests the Muller's ratchet hypothesis which concerns the evolution of dimorphic sex chromosomes. The distinctive organization of the X and Y sex chromosomes is responsible for sex-specific differences in the expression of many forms of hereditary disease. The X sex chromosome also appears to play a particularly important role in the process of adaptation, due to: 1) an enhanced level of expression of recessive, beneficial mutations, and 2) a form of sex specific gene expression for traits associated with sexual dimorphism. The proposed research will extend previous work which has demonstrated that the Muller's ratchet process can be effectively studied in the laboratory using a Drosophila melanogaster (common fruit fly) model system. The factors that affect the operation of the Muller's ratchet process are: mutation, selection, sampling error, and recombination. These factors also determine the size of the reservoir of disease-causing mutation that are maintained in human and other populations. The proposed research will permit us to better understand the dynamics of our own reservoir of deleterious mutations. The research used a D. melanogaster model system to study the rate of operation of the Muller's ratchet process in response to manipulative changes in its major parameters; the effective population size, and the presence/absence of recombination. This is accomplished by constructing giant chromosomes that are forced to segregate like either a primitive X (recombining) or Y (non-recombining) sex chromosomes and then measuring the rate of accumulation of deleterious mutations.

这项拟议中的研究验证了穆勒的棘轮假说 这是关于两性染色体的进化。 的 X和Y性染色体的独特组织是 负责性别特异性差异的表达， 多种遗传性疾病。 X性染色体也 似乎在这一过程中发挥着特别重要的作用， 适应，由于：1）增强的表达水平， 隐性的，有益的突变，和2）一种形式的性别特异性 与两性异形相关的性状的基因表达。 拟议的研究将扩展以前的工作， 证明了穆勒棘轮过程可以有效地 在实验室中使用果蝇（常见的 果蝇）模型系统。 影响手术的因素 穆勒的棘轮过程是：突变，选择， 抽样误差和重组。 这些因素也决定了 致病突变的储存量 在人类和其他人群中。 拟议研究 将使我们更好地了解我们自己的动态 有害突变的储存库。 该研究使用了D.黑腹模型系统， 研究了Muller棘齿过程的手术率， 对主要参数操纵性变化的反应; 有效人口规模，以及是否存在 重组 这是通过构建巨大的 染色体被迫分离，就像原始的 X（重组）或Y（非重组）性染色体，然后 测量有害突变的累积率。