Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK.
School of Life Science, Hunan University of Science and Technology, Xiangtan 411201, China.
Genes (Basel). 2020 May 31;11(6):610. doi: 10.3390/genes11060610.
Y-chromosomes contain a non-recombining region (NRY), and in many organisms it was shown that the NRY expanded over time. How and why the NRY expands remains unclear. Young sex chromosomes, where NRY expansion occurred recently or is on-going, offer an opportunity to study the causes of this process. Here, we used the plant , where sex chromosomes evolved ~11 million years ago, to study the location of the boundary between the NRY and the recombining pseudoautosomal region (PAR). The previous work devoted to the NRY/PAR boundary in was based on a handful of genes with locations approximately known from the genetic map. Here, we report the analysis of 86 pseudoautosomal and sex-linked genes adjacent to the NRY/PAR boundary to establish the location of the boundary more precisely. We take advantage of the dense genetic map and polymorphism data from wild populations to identify 20 partially sex-linked genes located in the "fuzzy boundary", that rarely recombines in male meiosis. Genes proximal to this fuzzy boundary show no evidence of recombination in males, while the genes distal to this partially-sex-linked region are actively recombining in males. Our results provide a more accurate location for the PAR boundary in , which will help to elucidate the causes of PAR boundary shifts leading to NRY expansion over time.
Y 染色体包含一个非重组区域（NRY），在许多生物中已经表明，NRY 随着时间的推移而扩张。NRY 如何以及为何扩张仍然不清楚。年轻的性染色体，其中 NRY 扩张最近发生或正在进行，为研究这一过程的原因提供了机会。在这里，我们利用植物，其性染色体在大约 1100 万年前进化，研究 NRY 和重组假常染色体区（PAR）之间的边界位置。之前在研究中的工作是基于少数几个基因，这些基因的位置大致从遗传图谱中得知。在这里，我们报告了对 86 个紧邻 边界的假常染色体和性连锁基因的分析，以更精确地确定边界的位置。我们利用来自野生种群的密集遗传图谱和多态性数据，鉴定了 20 个位于“模糊边界”的部分性连锁基因，这些基因在雄性减数分裂中很少发生重组。靠近这个模糊边界的基因在雄性中没有重组的证据，而远离这个部分性连锁区域的基因在雄性中则积极重组。我们的结果提供了 中 PAR 边界的更准确位置，这将有助于阐明导致 NRY 随时间扩张的 PAR 边界移动的原因。
