Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, Suita, Japan.
FEBS Open Bio. 2020 Apr;10(4):657-673. doi: 10.1002/2211-5463.12832. Epub 2020 Mar 19.
Rax is one of the key transcription factors crucial for vertebrate eye development. In this study, we conducted comprehensive evolutionary analysis of Rax. We found that Bilateria and Cnidaria possess Rax, but Placozoa, Porifera, and Ctenophora do not, implying that the origin of the Rax gene dates back to the common ancestor of Cnidaria and Bilateria. The results of molecular phylogenetic and synteny analyses on Rax loci between jawed and jawless vertebrates indicate that segmental duplication of the Rax locus occurred in an early common ancestor of jawed vertebrates, resulting in two Rax paralogs in jawed vertebrates, Rax and Rax2. By analyzing 86 mammalian genomes from all four major groups of mammals, we found that at least five independent Rax2 gene loss events occurred in mammals. This study may provide novel insights into the evolution of the eye.
Rax 是脊椎动物眼睛发育过程中关键的转录因子之一。在这项研究中，我们对 Rax 进行了全面的进化分析。我们发现，扁盘动物、多孔动物和栉水母没有 Rax，而两侧对称动物和刺胞动物拥有 Rax，这表明 Rax 基因的起源可以追溯到刺胞动物和两侧对称动物的共同祖先。通过对有颌和无颌脊椎动物 Rax 基因座之间的分子系统发育和基因同线性分析，我们发现，Rax 基因座的片段重复发生在有颌脊椎动物的早期共同祖先中，导致有颌脊椎动物中有两个 Rax 基因的旁系同源物，即 Rax 和 Rax2。通过分析来自四大哺乳动物类群的 86 种哺乳动物基因组，我们发现至少有五次 Rax2 基因的独立丢失事件发生在哺乳动物中。本研究可能为眼睛的进化提供新的见解。
