法国索邦大学Denis Roze课题组在研究中取得进展。他们发现在无性别二态性的情况下，Y染色体重组停止和退化。相关论文发表在2022年2月11日出版的《科学》杂志上。

他们研究了一种性染色体进化模型，该模型结合了基因表达的顺式和反式调节子的共同进化。他们表明，剂量补偿的早期出现通过产生性拮抗调节作用有利于维持 Y 连锁倒位。随后是由 X 和 Y 染色体之间的调节分歧引起的这些非重组倒位的退化。与当前的理论相反，整个过程的发生没有任何与性二态性相关的选择压力。

据了解，目前的理论认为退化的性染色体——例如哺乳动物的 Y——通过三个步骤进化：（i）重组停滞，将有益雄性的等位基因与 Y 染色体联系起来；(ii) Y 变性，这是由于在没有重组的情况下选择无效造成的；(iii) 剂量补偿，纠正雄性中 X 连锁基因的低表达。

附：英文原文

Title: Y recombination arrest and degeneration in the absence of sexual dimorphism

Author: Thomas Lenormand, Denis Roze

Issue&Volume: 2022-02-11

Abstract: Current theory proposes that degenerated sex chromosomes—such as the mammalian Y—evolve through three steps: (i) recombination arrest, linking male-beneficial alleles to the Y chromosome; (ii) Y degeneration, resulting from the inefficacy of selection in the absence of recombination; and (iii) dosage compensation, correcting the resulting low expression of X-linked genes in males. We investigate a model of sex chromosome evolution that incorporates the coevolution of cis and trans regulators of gene expression. We show that the early emergence of dosage compensation favors the maintenance of Y-linked inversions by creating sex-antagonistic regulatory effects. This is followed by degeneration of these nonrecombining inversions caused by regulatory divergence between the X and Y chromosomes. In contrast to current theory, the whole process occurs without any selective pressure related to sexual dimorphism.

DOI: abj1813

Source: https://www.science.org/doi/10.1126/science.abj1813