Kono Hiromitsu, Tamura Masaru, Osada Naoki, Suzuki Hitoshi, Abe Kuniya, Moriwaki Kazuo, Ohta Kunihiro, Shiroishi Toshihiko
Mammalian Genetics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan Department of Biophysics and Biochemistry, The University of Tokyo, Tokyo 153-8902, Japan.
Mammalian Genetics Laboratory, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.
DNA Res. 2014 Jun;21(3):315-26. doi: 10.1093/dnares/dst059. Epub 2014 Jan 20.
PR/SET domain containing 9 (Prdm9) mediates histone modifications such as H3K4me3 and marks hotspots of meiotic recombination. In many mammalian species, the Prdm9 gene is highly polymorphic. Prdm9 polymorphism is assumed to play two critical roles in evolution: to diversify the spectrum of meiotic recombination hotspots and to cause male hybrid sterility, leading to reproductive isolation and speciation. Nevertheless, information about Prdm9 sequences in natural populations is very limited. In this study, we conducted a comprehensive population survey on Prdm9 polymorphism in the house mouse, Mus musculus. Overall M. musculus Prdm9 displays an extraordinarily high level of polymorphism, particularly in regions encoding zinc finger repeats, which recognize recombination hotspots. Prdm9 alleles specific to various M. musculus subspecies dominate in subspecies territories. Moreover, introgression into other subspecies territories was found for highly divergent Prdm9 alleles associated with t-haplotype. The results of our phylogeographical analysis suggest that the requirement for hotspot diversity depends on geographical range and time span in mouse evolution, and that Prdm9 polymorphism has not been maintained by a simple balanced selection in the population of each subspecies.
含PR/SET结构域9（Prdm9）介导组蛋白修饰，如H3K4me3，并标记减数分裂重组热点。在许多哺乳动物物种中，Prdm9基因高度多态。Prdm9多态性被认为在进化中发挥两个关键作用：使减数分裂重组热点的谱多样化，并导致雄性杂种不育，从而导致生殖隔离和物种形成。然而，关于自然种群中Prdm9序列的信息非常有限。在本研究中，我们对家鼠（小家鼠）的Prdm9多态性进行了全面的种群调查。总体而言，小家鼠Prdm9表现出极高的多态性水平，尤其是在编码识别重组热点的锌指重复序列的区域。特定于小家鼠各个亚种的Prdm9等位基因在亚种区域占主导地位。此外，发现与t单倍型相关的高度分化的Prdm9等位基因渗入到其他亚种区域。我们的系统地理学分析结果表明，热点多样性的需求取决于小鼠进化中的地理范围和时间跨度，并且Prdm9多态性并非通过每个亚种种群中的简单平衡选择来维持。
