A recent publication describing the assembly of the Y chromosomes of 43 males was remarkable not only for its ambitious technical scope but also for the startling suggestion that the boundary of the pseudoautosomal region 1 (PAR1), where the human X and Y chromosomes engage in crossing-over during male meiosis, lies 500 kb distal to its previously reported location. Where is the boundary of the human PAR1? We first review the evidence that mapped the PAR boundary, or PAB, before the human genome draft sequence was produced, then examine post-genomic datasets for evidence of crossing-over between the X and Y, and lastly re-examine contiguous sequence assemblies of the PAR-NPY boundary to see whether they support a more distal PAB. We find ample evidence of X-Y crossovers throughout the 500 kb in question, some as close as 246 bp to the previously reported PAB. Our new analyses, combined with previous studies over the past 40 years, provide overwhelming evidence to support the original position and narrow the probable location of the PAB to a 201-bp window.

中文翻译：

---

人类伪常染色体区域的边界在哪里？


最近一篇描述43名男性Y染色体组装的出版物不仅因其雄心勃勃的技术范围而引人注目，还因为令人震惊地提出，即在男性减数分裂期间人类X和Y染色体进行交叉的假常染色体区域1（PAR1）的边界位于其先前报道的位置远端500 kb。人类 PAR1 的边界在哪里？我们首先回顾了在生成人类基因组草稿序列之前绘制 PAR 边界或 PAB 的证据，然后检查基因组后数据集以寻找 X 和 Y 之间交叉的证据，最后重新检查 PAR-NPY 边界的连续序列组装，看看它们是否支持更远的 PAB。我们发现在整个 500 kb 中发现了 X-Y 交叉的充分证据，其中一些接近于先前报道的 PAB 的 246 bp。我们的新分析，结合过去 40 年的先前研究，提供了压倒性的证据来支持原始位置，并将 PAB 的可能位置缩小到 201 个基点的窗口。