研究人员报告了对11个物种睾丸的单核转录组数据的演化分析，这些物种涵盖了三个主要的哺乳动物品系（真哺乳亚纲、有袋动物和单孔目动物）和鸟类（演化的外群），并包括7种灵长类动物。研究人员发现，睾丸的快速演化是由基因表达变化、氨基酸替换和生精后期新基因的加速固定率驱动的，这可能是由减少的多态性限制、单倍体选择和转录允许的染色质促成的。研究人员确定了不同物种间单个基因的时间表达变化以及控制祖先精子发生过程的保守表达程序。在演化过程中，主要在精原细胞（提供精子生成的生殖细胞）和Sertoli（体细胞支持）细胞中表达的基因在X染色体上累积，可能是由于对雄性有益的选择力量。
进一步的工作确定了含X和含Y的精子之间的转录组差异，并发现减数分裂性染色体失活（MSCI）也发生在单细胞动物中，因此是哺乳动物性染色体系统的共同点。因此，作为MSCI基础的未联会染色质的减数分裂沉默机制是哺乳动物的一个祖先特征。这个研究阐明了精子发生的分子演化和相关的选择力量，并为研究整个哺乳动物的睾丸生物学提供了资源。
据了解，睾丸通过精子发生产生配子，并在哺乳动物的形态学和分子水平上迅速演化，这可能是由于雄性动物在演化过程中面临着生殖成功的压力。然而，哺乳动物中单个精原细胞类型的分子演化在很大程度上仍未被描述。
附：英文原文
Title: The molecular evolution of spermatogenesis across mammals
Author: Murat, Florent, Mbengue, Noe, Winge, Sofia Boeg, Trefzer, Timo, Leushkin, Evgeny, Sepp, Mari, Cardoso-Moreira, Margarida, Schmidt, Julia, Schneider, Celine, Minger, Katharina, Brning, Thoomke, Lamanna, Francesco, Belles, Meritxell Riera, Conrad, Christian, Kondova, Ivanela, Bontrop, Ronald, Behr, Rdiger, Khaitovich, Philipp, Pbo, Svante, Marques-Bonet, Tomas, Grtzner, Frank, Almstrup, Kristian, Schierup, Mikkel Heide, Kaessmann, Henrik
Issue&Volume: 2022-12-21
Abstract: The testis produces gametes through spermatogenesis and evolves rapidly at both the morphological and molecular level in mammals1,2,3,4,5,6, probably owing to the evolutionary pressure on males to be reproductively successful7. However, the molecular evolution of individual spermatogenic cell types across mammals remains largely uncharacterized. Here we report evolutionary analyses of single-nucleus transcriptome data for testes from 11 species that cover the three main mammalian lineages (eutherians, marsupials and monotremes) and birds (the evolutionary outgroup), and include seven primates. We find that the rapid evolution of the testis was driven by accelerated fixation rates of gene expression changes, amino acid substitutions and new genes in late spermatogenic stages, probably facilitated by reduced pleiotropic constraints, haploid selection and transcriptionally permissive chromatin. We identify temporal expression changes of individual genes across species and conserved expression programs controlling ancestral spermatogenic processes. Genes predominantly expressed in spermatogonia (germ cells fuelling spermatogenesis) and Sertoli (somatic support) cells accumulated on X chromosomes during evolution, presumably owing to male-beneficial selective forces. Further work identified transcriptomal differences between X- and Y-bearing spermatids and uncovered that meiotic sex-chromosome inactivation (MSCI) also occurs in monotremes and hence is common to mammalian sex-chromosome systems. Thus, the mechanism of meiotic silencing of unsynapsed chromatin, which underlies MSCI, is an ancestral mammalian feature. Our study illuminates the molecular evolution of spermatogenesis and associated selective forces, and provides a resource for investigating the biology of the testis across mammals.
DOI: 10.1038/s41586-022-05547-7
Source: https://www.nature.com/articles/s41586-022-05547-7
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
