EAGER: The evolutionary consequences of subtle biases in the outcome of meiosis

孟德尔遗传学的核心假设是，一个人从母亲那里获得的基因与从父亲那里获得的基因一样有很好的机会遗传下去。总体而言，这一假设成立。然而，令人震惊的例外是，在经过充分研究的植物和动物中，母亲或父亲的基因自私地传递给下一代。这些案例是罕见的例外，还是非孟德尔式的冰山一角？新的遗传工具现在使研究人员能够在野生动植物中发现更多微妙的偏离50：50的比例，这表明自私基因可能比以前认识到的更频繁和多样化。这一点很重要，因为即使是导致基因异常的基因，如果它有略高于50：50的机会传给下一代，也可以持续存在。该项目将研究基因非50：50传递对苔藓模型系统Ceratodon Purpureus适合度的影响。结合新的数学模型和来自这一简单苔藓系统的遗传数据，将揭示不孕不育的遗传学、繁殖的结果及其对基因组结构的影响。这项提案提出了一个全面的计划，将全基因组范围的分离扭曲模式与苔藓模型系统Ceratodon Purpureus的适合性联系起来。PI的中心假设是，分离扭曲在整个基因组中很常见，并有助于保持遗传变异以适应，这是进化生物学的中心问题之一。这一建议的基本原理是开发一种新的系统，在机械水平上理解减数分裂结果和数量性状变异之间以前未被探索的联系。为了实现这一目标，PI将把来自紫锥菊自然种群的全基因组多态数据与新的统计模型结合起来，该模型将分离比视为一个数量性状，其结构将被推断。由于苔藓具有单倍体主导的生命周期，PI可以有效地调查减数分裂的产物，并对自然种群中表现出偏向传递和适合度变异的基因之间的特定关联进行简单而强大的测试。

The central assumption of Mendelian genetics is that an individual has as good a chance of passing on a gene that it received from its mother as one that it received from its father. In general, this assumption holds. Yet striking exceptions, in which either the maternal or paternal gene selfishly transmits itself to the next generation, are known from well-studied plants and animals. Are these cases rare exceptions, or are they the tip of a non-Mendelian iceberg? New genetic tools have now enabled researchers to find more subtle deviations from 50:50 ratios in wild plants and animals, suggesting that selfish genes may be more frequent and varied than previously appreciated. This is important because even a gene that causes a genetic abnormality can persist if it has a slightly better than 50:50 chance of making it to the next generation. This project will study the effects of non-50:50 transmission of genes on fitness in the moss model system Ceratodon purpureus. Combining new mathematical models and genetic data from this simple moss system will reveal insight into the genetics of infertility, the outcome of reproduction, and its influence on the structure of the genome. This proposal presents a comprehensive plan to link genome-wide patterns of segregation distortion with fitness in the moss model system Ceratodon purpureus. The PIs central hypothesis is that segregation distortion is common across the genome and contributes to the maintenance of genetic variation for fitness, one of the central problems in evolutionary biology. The rationale for this proposal is to develop a new system to understand, at a mechanistic level, previously unexplored links between the outcome of meiosis and quantitative trait variation. To accomplish this goal, the PIs will combine genome-wide polymorphism data from natural populations of C. purpureus with new statistical models that treat segregation ratio as a quantitative trait whose architecture will be inferred. Because mosses have a haploid-dominant lifecycle, the PIs can efficiently survey the products of meiosis and generate simple yet powerful tests for specific associations between genes exhibiting biased transmission and fitness variation in natural populations.