Department of Animal Science, Center for Reproductive Biology and Health, College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA; email:
Annu Rev Anim Biosci. 2019 Feb 15;7:103-124. doi: 10.1146/annurev-animal-020518-115332. Epub 2018 Nov 9.
Mammalian sex chromosomes evolved from an ordinary pair of autosomes. The X chromosome is highly conserved, whereas the Y chromosome varies among species in size, structure, and gene content. Unlike autosomes that contain randomly mixed collections of genes, the sex chromosomes are enriched in testis-biased genes related to sexual development and reproduction, particularly in spermatogenesis and male fertility. This review focuses on how sex chromosome dosage compensation takes place and why meiotic sex chromosome inactivation occurs during spermatogenesis. Furthermore, the review also emphasizes how testis-biased genes are enriched on the sex chromosomes and their functions in male fertility. It is concluded that sex chromosomes are critical to sexual development and male fertility; however, our understanding of how sex chromosome genes direct sexual development and fertility has been hampered by the structural complexities of the sex chromosomes and by the multicopy nature of the testis gene families that also play a role in immunity, cancer development, and brain function.
哺乳动物的性染色体是由一对常染色体演变而来的。X 染色体高度保守，而 Y 染色体在大小、结构和基因含量方面在物种间存在差异。与包含随机混合基因的常染色体不同，性染色体富含与性发育和生殖相关的睾丸偏倚基因，特别是在精子发生和男性生育力方面。本综述重点介绍了性染色体剂量补偿是如何发生的，以及为什么减数分裂性染色体失活会在精子发生过程中发生。此外，该综述还强调了睾丸偏倚基因是如何在性染色体上富集的，以及它们在男性生育力中的作用。结论是，性染色体对性发育和男性生育力至关重要；然而，由于性染色体的结构复杂性以及在免疫、癌症发展和大脑功能中也发挥作用的睾丸基因家族的多拷贝性质，我们对性染色体基因如何指导性发育和生育力的理解受到了阻碍。
