CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, s/n, 4450-208 Porto, Portugal; ICBAS, Institute of Biomedical Sciences Abel Salazar, University of Porto, Portugal.
CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Avenida General Norton de Matos, s/n, 4450-208 Porto, Portugal.
Genomics. 2022 Jul;114(4):110419. doi: 10.1016/j.ygeno.2022.110419. Epub 2022 Jun 24.
Sex chromosomes recombine restrictly in their homologous area, the pseudoautosomal region (PAR), represented by PAR1 and PAR2, which behave like an autosome in both pairing and recombination. The PAR1, common to most of the eutherian mammals, is located at the terminus of the sex chromosomes short arm and exhibit recombination rates ~20 times higher than the autosomes. Here, we assessed the interspecific evolutionary genomic dynamics of 15 genes of the PAR1 across 41 mammalian genera (representing six orders). The strong negative selection detected in most of the assessed groups reinforces the presence of evolutionary constraints, imposed by the important function of the PAR1 genes. Indeed, mutations in these genes are associated with various diseases in humans, including stature problems (Klinefelter Syndrome), leukemia and mental diseases. Yet, a few genes exhibiting positive selection (ω-value >1) were depicted in Rodentia (ASMT and ZBED1) and Primates (CRLF2 and CSF2RA). Rodents have the smallest described PAR1, while that of simian primates/humans underwent a 3 to 5 fold size reduction. The assessment of the PAR1 genes synteny revealed differences among the mammalian species, especially in the Rodentia order where chromosomic translocations from the sex chromosomes to the autosomes were observed. Such syntenic changes may be an evidence of the rapid evolution in rodents, as previous referred in other papers, also depicted by their increased branch lengths in the phylogenetic analyses. Concluding, we suggest that genome migration is an important factor influencing the evolution of mammals and may result in changes of the selective pressures operating on the genome.
性染色体在同源区域（PAR）中进行有限的重组，PAR 由 PAR1 和 PAR2 组成，它们在配对和重组方面表现得像常染色体。PAR1 存在于大多数真兽类哺乳动物中，位于性染色体短臂的末端，其重组率比常染色体高约 20 倍。在这里，我们评估了 PAR1 中 15 个基因在 41 个哺乳动物属（代表六个目）之间的种间进化基因组动态。在大多数评估的群体中检测到的强烈负选择加强了 PAR1 基因的重要功能所带来的进化约束。事实上，这些基因的突变与人类的各种疾病有关，包括身材问题（克莱恩费尔特综合征）、白血病和精神疾病。然而，一些表现出正选择（ω值>1）的基因在啮齿动物（ASMT 和 ZBED1）和灵长类动物（CRLF2 和 CSF2RA）中被描绘出来。啮齿动物的 PAR1 是描述最小的，而灵长类动物/人类的 PAR1 经历了 3 到 5 倍的大小减少。对 PAR1 基因的同线性评估显示了哺乳动物物种之间的差异，特别是在啮齿动物目中，观察到了从性染色体到常染色体的染色体易位。这种同线性变化可能是啮齿动物快速进化的证据，正如之前在其他论文中所提到的，也通过它们在系统发育分析中的分支长度增加得到了描绘。总之，我们认为基因组迁移是影响哺乳动物进化的一个重要因素，可能导致作用于基因组的选择压力发生变化。
