Genetic Analysis of Coadaptation and Hybrid Breakdown

共适应和杂交分解的遗传分析

• 批准号: 9815424
• 负责人: Ronald Burton
• 金额: $ 28.4万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-15 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9815424&HistoricalAwards=false
• 关键词: Genetic; Analysis; Coadaptation; Hybrid; Breakdown

9815424BurtonIsolated populations within species gradually diverge genetically through the combined effects of mutation, genetic drift, and natural selection. Two types of selection may be important: (1) selection for adaptation to local environments (which has received wide attention), and (2) selection favoring coadapted sets of alleles within each population. The proposed work focuses on the latter process, which has been relatively understudied.Coadaptation is best observed in laboratory crosses between individuals from isolated populations. Such crosses typically result in reduced physiological performance in second-generation hybrids as the coadapted sets of alleles within each population are disrupted by recombination. Using the copepod Tigriopus californicus as a model system, the proposed experiments will assess the level of coadaptation in two physiological/genetic systems: (1) activity of the enzyme cytochrome c oxidase, and (2) rates of transcription of ribosomal RNA genes. Both these systems are known to require extensive gene interaction, making them especially likely to experience selection for coadaptation.The proposed studies of coadaptation within populations are fundamental to understanding the importance of genetic variation within and between natural populations. Although the maintenance of genetic diversity is often espoused as a primary goal of conservation efforts, the extent to which such variation is vital to the ecology and evolution of species is poorly understood. By focusing on the function of genetic diversity in natural populations, the proposed work may provide a firmer experimental basis for such conservation efforts.

通过突变、遗传漂移和自然选择的综合作用，物种内孤立的种群逐渐在遗传上分化。两种类型的选择可能是重要的：(1)适应当地环境的选择(已受到广泛关注)和(2)有利于每个种群内共适应的等位基因集的选择。拟议的工作重点放在后一种过程上，这一过程一直被相对研究得较少。共同适应最好在实验室观察到来自孤立种群的个体之间的杂交。这种杂交通常会导致第二代杂交种的生理表现下降，因为每个种群内的共适应等位基因集会被重组打乱。以加州虎脚类为模型系统，本实验将评估两个生理/遗传系统的共适应水平：(1)细胞色素c氧化酶的活性；(2)核糖体RNA基因的转录速率。众所周知，这两个系统都需要广泛的基因相互作用，使得它们特别可能经历共同适应的选择。拟议的群体内共同适应研究是理解自然群体内和自然群体之间遗传变异的重要性的基础。虽然维持遗传多样性通常被认为是保护工作的主要目标，但这种变异对物种的生态和进化至关重要的程度却鲜为人知。通过关注遗传多样性在自然种群中的作用，拟议的工作可能会为这种保护努力提供更坚实的实验基础。