Department of Biology, University of Rochester, Rochester, NY 14627, USA.
Proc Biol Sci. 2023 Nov 8;290(2010):20231823. doi: 10.1098/rspb.2023.1823. Epub 2023 Nov 1.
Sex chromosomes are havens for intragenomic conflicts. The absence of recombination between sex chromosomes creates the opportunity for the evolution of segregation distorters: selfish genetic elements that hijack different aspects of an individual's reproduction to increase their own transmission. Biased (non-Mendelian) segregation, however, often occurs at a detriment to their host's fitness, and therefore can trigger evolutionary arms races that can have major consequences for genome structure and regulation, gametogenesis, reproductive strategies and even speciation. Here, we review an emerging feature from comparative genomic and sex chromosome evolution studies suggesting that meiotic drive is pervasive: the recurrent evolution of paralogous sex-linked gene families. Sex chromosomes of several species independently acquire and co-amplify rapidly evolving gene families with spermatogenesis-related functions, consistent with a history of intragenomic conflict over transmission. We discuss Y chromosome features that might contribute to the and of evolution of X/Y co-amplified gene families, as well as their implications for the evolution of complexity in the genome. Finally, we propose a framework that explores the conditions that might allow for recurrent bouts of fixation of drivers and suppressors, in a dosage-sensitive fashion, and therefore the co-amplification of multigene families on sex chromosomes.
性染色体是基因组内冲突的避难所。性染色体之间缺乏重组为分离干扰因子（自私的遗传因子，它们劫持个体繁殖的不同方面来增加自身的传播）的进化创造了机会。然而，偏置（非孟德尔）分离往往以牺牲宿主适应性为代价，因此可能引发进化军备竞赛，对基因组结构和调控、配子发生、生殖策略甚至物种形成产生重大影响。在这里，我们回顾了比较基因组学和性染色体进化研究中出现的一个新特征，即减数分裂驱动是普遍存在的：与精子发生相关功能的同源性连锁基因家族的反复进化。几个物种的性染色体独立地获得并共同扩增具有快速进化功能的基因家族，与基因组内的传播过程中的遗传冲突相一致。我们讨论了 Y 染色体的特征，这些特征可能有助于 X/Y 共同扩增基因家族的进化，以及它们对基因组复杂性进化的影响。最后，我们提出了一个框架，探讨了在剂量敏感的情况下，以反复固定驱动因子和抑制因子的方式，以及在性染色体上共同扩增多基因家族的条件。
