Division of Protein Expression & Modification, New England Biolabs, Ipswich, MA, 01938, USA.
Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY, 10003, USA.
Nat Commun. 2020 Apr 23;11(1):1964. doi: 10.1038/s41467-020-15654-6.
Sex determination mechanisms often differ even between related species yet the evolution of sex chromosomes remains poorly understood in all but a few model organisms. Some nematodes such as Caenorhabditis elegans have an XO sex determination system while others, such as the filarial parasite Brugia malayi, have an XY mechanism. We present a complete B. malayi genome assembly and define Nigon elements shared with C. elegans, which we then map to the genomes of other filarial species and more distantly related nematodes. We find a remarkable plasticity in sex chromosome evolution with several distinct cases of neo-X and neo-Y formation, X-added regions, and conversion of autosomes to sex chromosomes from which we propose a model of chromosome evolution across different nematode clades. The phylum Nematoda offers a new and innovative system for gaining a deeper understanding of sex chromosome evolution.
性别决定机制即使在相关物种之间也常常不同，但除了少数几个模式生物外，性染色体的进化仍知之甚少。一些线虫，如秀丽隐杆线虫，具有 XO 性别决定系统，而其他线虫，如丝虫寄生虫布鲁氏菌，具有 XY 机制。我们展示了完整的布鲁氏菌基因组组装，并定义了与秀丽隐杆线虫共享的 Nigon 元件，然后将其映射到其他丝虫物种和更远缘的线虫基因组上。我们发现性染色体进化具有惊人的可塑性，存在几种新的 X 和 Y 形成、X 附加区域以及常染色体向性染色体的转化的明显案例，从中我们提出了一个跨不同线虫类群的染色体进化模型。线虫门为更深入地了解性染色体进化提供了一个新的、创新的系统。
