Fujian Key Laboratory of Special Marine Bio-resources Sustainable Utilization & Fujian Key Laboratory of Developmental and Neurobiology, College of Life Sciences, Fujian Normal University, Fuzhou, Fujian 350117, China.
Fujian-Macao Science and Technology Cooperation Base of Traditional Chinese Medicine-Oriented Chronic Disease Prevention and Treatment, Innovation and Transformation Center, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350108, China.
Proc Natl Acad Sci U S A. 2023 Mar 7;120(10):e2201504120. doi: 10.1073/pnas.2201504120. Epub 2023 Mar 3.
The slow-evolving invertebrate amphioxus has an irreplaceable role in advancing our understanding of the vertebrate origin and innovations. Here we resolve the nearly complete chromosomal genomes of three amphioxus species, one of which best recapitulates the 17 chordate ancestor linkage groups. We reconstruct the fusions, retention, or rearrangements between descendants of whole-genome duplications, which gave rise to the extant microchromosomes likely existed in the vertebrate ancestor. Similar to vertebrates, the amphioxus genome gradually establishes its three-dimensional chromatin architecture at the onset of zygotic activation and forms two topologically associated domains at the gene cluster. We find that all three amphioxus species have ZW sex chromosomes with little sequence differentiation, and their putative sex-determining regions are nonhomologous to each other. Our results illuminate the unappreciated interspecific diversity and developmental dynamics of amphioxus genomes and provide high-quality references for understanding the mechanisms of chordate functional genome evolution.
在推进我们对脊椎动物起源和创新的理解方面，演化缓慢的无脊椎动物文昌鱼具有不可替代的作用。在这里，我们解析了三种文昌鱼物种的近乎完整的染色体基因组，其中一种最能重现 17 条脊索动物祖先连锁群。我们重建了全基因组加倍的后代之间的融合、保留或重排，这导致了现存的微染色体可能存在于脊椎动物的祖先中。与脊椎动物相似，文昌鱼基因组在合子激活开始时逐渐建立其三维染色质结构，并在基因簇处形成两个拓扑关联域。我们发现，这三种文昌鱼都有性染色体 ZW，其序列差异很小，它们的假定性别决定区域彼此之间没有同源性。我们的研究结果阐明了文昌鱼基因组在种间的多样性和发育动态方面的未知内容，并为理解脊索动物功能基因组进化的机制提供了高质量的参考。
