O'Neill Ryan S, Clark Denise V
Department of Biology, University of New Brunswick, 10 Bailey Drive, Fredericton, NB, Canada E3B 5A3.
Int J Evol Biol. 2013;2013:693085. doi: 10.1155/2013/693085. Epub 2013 Jun 5.
Retrogenes form a class of gene duplicate lacking the regulatory sequences found outside of the mRNA-coding regions of the parent gene. It is not clear how a retrogene's lack of parental regulatory sequences affects the evolution of the gene pair. To explore the evolution of parent genes and retrogenes, we investigated three such gene pairs in the family Drosophilidae; in Drosophila melanogaster, these gene pairs are CG8331 and CG4960, CG17734 and CG11825, and Sep2 and Sep5. We investigated the embryonic expression patterns of these gene pairs across multiple Drosophila species. Expression patterns of the parent genes and their single copy orthologs are relatively conserved across species, whether or not a species has a retrogene copy, although there is some variation in CG8331 and CG17734. In contrast, expression patterns of the retrogene orthologs have diversified. We used the genome sequences of 20 Drosophila species to investigate coding sequence evolution. The coding sequences of the three gene pairs appear to be evolving predominantly under negative selection; however, the parent genes and retrogenes show some distinct differences in amino acid sequence. Therefore, in general, retrogene expression patterns and coding sequences are distinct compared to their parents and, in some cases, retrogene expression patterns diversify.
反转录基因构成了一类基因复制体，其缺乏在亲本基因的mRNA编码区域之外发现的调控序列。尚不清楚反转录基因缺乏亲本调控序列如何影响基因对的进化。为了探究亲本基因和反转录基因的进化，我们研究了果蝇科中的三对这样的基因对；在黑腹果蝇中，这些基因对分别是CG8331和CG4960、CG17734和CG11825，以及Sep2和Sep5。我们研究了这些基因对在多个果蝇物种中的胚胎表达模式。亲本基因及其单拷贝直系同源基因的表达模式在物种间相对保守，无论一个物种是否有反转录基因拷贝，尽管CG8331和CG17734存在一些变异。相比之下，反转录基因直系同源基因的表达模式已经多样化。我们利用20种果蝇的基因组序列来研究编码序列的进化。这三对基因的编码序列似乎主要在负选择下进化；然而，亲本基因和反转录基因在氨基酸序列上表现出一些明显的差异。因此，一般来说，反转录基因的表达模式和编码序列与其亲本不同，并且在某些情况下，反转录基因的表达模式会多样化。
