Comparative studies on duplicated tdrd7 paralogs in teleosts: Molecular evolution caused neo-functionalization

In this study, two teleost tdrd7 genes (tdrd7a and tdrd7b) were identified in the transcriptome of Japanese flounder (Paralichthys olivaceus). Through genomic structure, phylogenetic, synteny analysis and online bioinformatic mining of tdrd7 duplications in other selected species, we confirmed that tdrd7a/7b were originated from the teleost-specific 3R-WGD. The tdrd7a is specific to teleost except for spotted gar. The tdrd7a showed higher molecular evolution rate than tdrd7b with longer branch-length in the phylogenetic tree and multiple positively selected sites. Interestingly, it showed gonad specific expression pattern in adult tissues and germ cell specific distribution in embryos and gonads. Its 3′-untranslated region (3′UTR) labeled eGFP/DsRED could visualize primordial germ cells (PGCs) in zebrafish embryos. The tdrd7b did not show similar tissue and cell type specificity. These characteristic differences between the duplicated tdrd7 paralogues provided evidence that tdrd7a and tdrd7b had experienced neofunctionalization in Japanese flounder. Our results provided novel insights into the evolution and functional diversification of teleost tdrd7 genes deserving further investigations.Graphical abstract
Source: Comparative Biochemistry and Physiology Part D: Genomics and Proteomics - Category: Genetics & Stem Cells Source Type: research