Fukui Akimasa, Matsunami Masatoshi
Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Bunkyo-ku, Tokyo, Japan.
Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan.
Front Genet. 2022 Jan 20;12:787979. doi: 10.3389/fgene.2021.787979. eCollection 2021.
Chemokines, relatively small secreted proteins, are involved in cell migration and function in various biological events, including immunity, morphogenesis, and disease. Due to their nature, chemokines tend to be a target of hijacking of immunity by virus and therefore show an exceptionally high mutation rate. is considered an excellent model to investigate the effect of whole-genome duplication for gene family evolution. Because its allotetraploidization occurred around 17-18 million years ago, ancestral subgenomes L and S were well conserved. Based on the gene model of human and diploid frog , we identified 52 chemokine genes and 26 chemokine receptors in . The retention rate of the gene in the L and S subgenomes was 96% (45/47) and 68% (32/47), respectively. We conducted molecular phylogenetic analysis and found clear orthologies in all receptor genes but not in the ligand genes, suggesting rapid divergences of the ligand. calculation demonstrated that ratio greater than one was observed in the four ligand genes, , , , and , but nothing in receptor genes. These results revealed that the whole-genome duplication promotes diversification of chemokine ligands in while conserving the genes necessary for homeostasis, suggesting that selective pressure also supports a rapid divergence of the chemokines in amphibians.
趋化因子是相对较小的分泌蛋白，参与细胞迁移以及包括免疫、形态发生和疾病在内的各种生物事件中的功能。由于其特性，趋化因子往往成为病毒劫持免疫的目标，因此显示出异常高的突变率。[具体物种名称]被认为是研究全基因组复制对基因家族进化影响的优秀模型。因为其异源四倍体化发生在大约1700 - 1800万年前，祖先亚基因组L和S保存完好。基于人类和二倍体青蛙[具体物种名称]的基因模型，我们在[具体物种名称]中鉴定出52个趋化因子基因和26个趋化因子受体。该基因在L和S亚基因组中的保留率分别为96%（45/47）和68%（32/47）。我们进行了分子系统发育分析，发现所有受体基因中都有明确的直系同源关系，但配体基因中没有，这表明配体的快速分化。[具体计算名称]计算表明，在四个配体基因[具体基因名称]、[具体基因名称]、[具体基因名称]和[具体基因名称]中观察到大于1的[具体比例名称]比值，但受体基因中没有。这些结果表明，全基因组复制促进了[具体物种名称]中趋化因子配体的多样化，同时保留了内环境稳定所需的基因，并表明选择压力也支持两栖动物趋化因子的快速分化。
