Inbreeding Depression in Metapopulations: Epistasis and Purging

近交种群中的近亲衰退：上位性和清除

• 批准号: 0212582
• 负责人: Michael Wade
• 金额: $ 33.9万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2005-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0212582&HistoricalAwards=false
• 关键词: Inbreeding; Depression; Metapopulations; Epistasis; Purging

This research investigates the contribution of gene interactions to inbreeding depression, the decline in viability and reproduction that affects the offspring of close genetic relatives. Over many generations, inbreeding depression can be mitigated or "purged" as natural selection removes deleterious genes and gene combinations from inbreeding populations. Using a combination of theory and experiment, with flour beetles as the model system, this research investigates the rate of inbreeding depression and the rate of purging for single genes and gene combinations. Conservation strategies for managing the genetics of endangered species use elaborate pedigrees designed to minimize inbreeding depression. Because they mitigate inbreeding, they necessarily mitigate purging. These management strategies are based upon single-gene theory. When inbreeding depression is caused by gene interactions, it can accumulate faster or slower than expected from single-gene theory. Thus, current conservation practice might be either overly elaborate or hopelessly inadequate for its goal of minimizing inbreeding depression. In addition, a balance between inbreeding and purging might represent the best strategy in the long run. With gene interactions, purging by selection removes groups of deleterious interacting genes and be much faster than the rate predicted by single-gene theory, where genes are removed independently, one at a time.

这项研究调查了基因相互作用对近亲繁殖衰退的贡献，影响近亲后代的生存能力和繁殖能力下降。经过许多代之后，随着自然选择从近亲繁殖种群中去除有害基因和基因组合，近亲繁殖衰退可以得到缓解或“清除”。本研究采用理论与实验相结合的方法，以面粉甲虫为模式系统，研究了单基因和基因组合的近交衰退率和清除率。 管理濒危物种遗传学的保护策略使用精心设计的谱系，旨在最大限度地减少近交衰退。因为它们减少了近亲繁殖，它们必然减少了净化。这些管理策略是基于单基因理论。当近亲繁殖衰退是由基因相互作用引起时，它的积累可能比单基因理论所预期的更快或更慢。因此，目前的保护实践可能要么过于复杂，要么无法达到最大限度地减少近亲繁殖衰退的目标。此外，从长远来看，近亲繁殖和清除之间的平衡可能是最好的策略。在基因相互作用的情况下，通过选择清除会去除有害的相互作用基因组，而且比单基因理论预测的速度要快得多，单基因理论中的基因是一次一个地被独立去除的。