Department of Biology, Evolutionary Biology, Copenhagen University, Copenhagen, Denmark.
Heredity (Edinb). 2010 Sep;105(3):290-8. doi: 10.1038/hdy.2009.193. Epub 2010 Jan 27.
As all four meiotic products give rise to sperm in males, female meiosis result in a single egg in most eukaryotes. Any genetic element with the potential to influence chromosome segregation, so that it is preferentially included in the egg, should therefore gain a transmission advantage; a process termed female meiotic drive. We are aware of two chromosomal components, centromeres and telomeres, which share the potential to influence chromosome movement during meioses and make the following predictions based on the presence of female meiotic drive: (1) centromere-binding proteins should experience rapid evolution as a result of a conflict between driving centromeres and the rest of the genome; and (2) segregation patterns should be skewed near centromeres and telomeres. To test these predictions, we first analyze the molecular evolution of seven centromere-binding proteins in nine divergent bird species. We find strong evidence for positive selection in two genes, lending support to the genomic conflict hypothesis. Then, to directly test for the presence of segregation distortion, we also investigate the transmission of approximately 9000 single-nucleotide polymorphisms in 197 chicken families. By simulating fair Mendelian meioses, we locate chromosomal regions with statistically significant transmission ratio distortion. One region is located near the centromere on chromosome 1 and a second region is located near the telomere on the p-arm of chromosome 1. Although these observations do not provide conclusive evidence in favour of the meiotic drive/genome conflict hypothesis, they do lend support to the hypothesis that centromeres and telomeres drive during female meioses in chicken.
在雄性中，所有四个减数分裂产物都会产生精子，而在大多数真核生物中，减数分裂会导致一个卵子的产生。任何具有影响染色体分离潜力的遗传元件，使其优先包含在卵子中，因此应该获得传递优势；这一过程被称为雌性减数分裂驱动。我们知道有两个染色体成分，着丝粒和端粒，它们都有可能在减数分裂过程中影响染色体运动，并根据雌性减数分裂驱动的存在做出以下预测：（1）着丝粒结合蛋白由于驱动着丝粒和基因组其余部分之间的冲突，应该经历快速进化；（2）分离模式应该在着丝粒和端粒附近倾斜。为了检验这些预测，我们首先分析了九个不同鸟类物种中七种着丝粒结合蛋白的分子进化。我们在两个基因中发现了强烈的正选择证据，这支持了基因组冲突假说。然后，为了直接检验分离扭曲的存在，我们还在 197 个鸡家族中调查了大约 9000 个单核苷酸多态性的传递。通过模拟公平的孟德尔减数分裂，我们定位了具有统计学意义的传递比扭曲的染色体区域。一个区域位于 1 号染色体的着丝粒附近，另一个区域位于 1 号染色体的 p 臂的端粒附近。尽管这些观察结果并没有为减数分裂驱动/基因组冲突假说提供确凿的证据，但它们确实支持了这样一种假设，即着丝粒和端粒在鸡的雌性减数分裂中起驱动作用。
