title: Evolution history of duplicatedsmad3genes in teleost: insights from Japanese flounder,Paralichthys olivaceus.
abstract: Following the two rounds of whole-genome duplication (WGD) during deuterosome evolution, a third genome duplication occurred in the ray-fined fish lineage and is considered to be responsible for the teleost-specific lineage diversification and regulation mechanisms. As a receptor-regulated SMAD (R-SMAD), the function ofSMAD3was widely studied in mammals. However, limited information of its role or putative paralogs is available in ray-finned fishes. In this study, twoSMAD3paralogs were first identified in the transcriptome and genome of Japanese flounder (Paralichthys olivaceus). We also exploredSMAD3duplication in other selected species. Following identification, genomic structure, phylogenetic reconstruction, and synteny analyses performed by MrBayes and online bioinformatic tools confirmed thatsmad3a/3bmost likely originated from the teleost-specific WGD. Additionally, selection pressure analysis and expression pattern of the two genes performed by PAML and quantitative real-time PCR (qRT-PCR) revealed evidence of subfunctionalization of the twoSMAD3paralogs in teleost. Our results indicate that twoSMAD3genes originate from teleost-specific WGD, remain transcriptionally active, and may have likely undergone subfunctionalization. This study provides novel insights to the evolution fates ofsmad3a/3band draws attentions to future function analysis ofSMAD3gene family.
authors.affiliation: Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong , China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Du
authors.affiliation: Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong , China.
authors.forename: Yuezhong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong , China.
authors.forename: Jinxiang
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong , China.
authors.forename: Quanqi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China , Qingdao, Shandong , China.
authors.forename: Xubo
authors.initials: X
authors.lastname: Wang
keywords: Genome duplication; Selective pressure; Smad3; Subfunctionalization