大豆蛋白编码基因起源与进化

物种基因组成是一个高度动态的进化过程, 其中相对较近起源的种系和物种特异性基因会持续整合到包含古老基因的原始基因网络中。新基因在塑造基因组结构中发挥重要作用, 能提高物种适应性。基因复制和新基因的从头起源是产生新基因及改变基因家族大小的2种方式。目前, 大豆(Glycine max)基因起源时间与进化模式的相互联系很大程度上还未被探索。该研究选择19种具有代表性的被子植物基因组, 分析基因含量动态性与大豆基因起源之间的潜在联系。采用基因出现法, 研究显示约58.7%的大豆基因能追溯到大约1.5亿年前, 同时有21.7%的基因为最近起源的orphan基因。研究结果表明, 与新基因相比, 古老基因受到更强的负选择压并且更加保守。此外, 古老基因的表达水平更高且更可能发生选择性剪切。此外, 具有不同拷贝数的基因在上述特征中也具有明显差异。研究结果有助于认识不同年龄基因的进化模式。

Origin and Evolution of Soybean Protein-coding Genes

The evolution of gene composition of a species is a highly dynamic process, wherein lineage- and species-specific genes originated relatively recently are continuously integrated into the original gene network of older genes. These young genes play important roles in shaping the genome architecture, thereby leading to improved adaptation for organisms. Gene duplication and de novo origination of new genes are two ways to create new genes, causing different gene families with various copy numbers. To what extent and how the evolutionary pattern of genes depends on the timing of gene origination are still largely unexplored in soybean. In this study, we selected 19 representative angiosperms and analyzed the potential relations of the gene content dynamics with the origination of soybean (Glycine max) genes. Using the gene emergence approach, we found that 58.7% of soybean genes could be dated to ~150 million years ago and 21.7% orphan genes had recently originated. As expected, in comparison with young genes, older genes tend to be subjected to stronger purifying selection and were more conserved. In addition, older genes featured higher expression levels and were more likely to undergo alternative splicing. Furthermore, genes with different copy numbers showed a difference in these aspects. These findings may help understand the evolutionary models of genes with different ages.