Gene conversion yields novel gene combinations in paralogs of GOT1 in the copepod Tigriopus californicus

Background: Gene conversion of duplicated genes can slow the divergence of paralogous copies over time but can also result in other interesting evolutionary patterns. Islands of genetic divergence that persist in the face of gene conversion can point to gene regions undergoing selection for new functions. Novel combinations of genetic variation that differ greatly from the original sequence can result from the transfer of genetic variation between paralogous genes by rare gene conversion events. Genetically divergent populations of the copepod Tigriopus californicus provide an excellent model to look at the patterns of divergence among paralogs across multiple independent evolutionary lineages. Results: In this study the evolution of a set of paralogous genes encoding putative aspartate transaminase proteins (called GOT1 here) are examined in populations of the copepod T. californicus. One pair of duplicated genes, GOT1p1 and GOT1p2, has regions of high divergence between the copies in ...背景：重复基因的基因转换（gene conversion）可随时间推移减缓旁系同源拷贝（paralogous copies）间的序列分化，同时也能催生其他颇具研究价值的进化模式。在基因转换作用下仍得以保留的遗传分化岛，可指向正经历新功能选择的基因区域。罕见的基因转换事件可在旁系同源基因（paralogous genes）间传递遗传变异，进而形成与原始序列差异显著的全新遗传变异组合。加州猛水蚤（Tigriopus californicus，隶属于桡足类（copepod））的遗传分化种群，为研究多个独立进化谱系中旁系同源基因间的分化模式提供了极佳的研究模型。结果：本研究以加州猛水蚤（T. californicus）种群为研究对象，对一组编码推定天冬氨酸转氨酶（putative aspartate transaminase）的旁系同源基因（本文中命名为GOT1）的进化情况展开分析。其中一对重复基因GOT1p1与GOT1p2，其拷贝间存在高分化区域……