Rapid evolution of piRNA pathway in the teleost fish: implication for an adaptation to transposon diversity.
The Piwi-interacting RNA (piRNA) pathway is responsible for germline specification, gametogenesis, transposon silencing, and genome integrity. Transposable elements can disrupt genome and its functions. However, piRNA pathway evolution and its adaptation to transposon diversity in the teleost fish remain unknown. This article unveils evolutionary scene of piRNA pathway and its association with diverse transposons by systematically comparative analysis on diverse teleost fish genomes. Selective pressure analysis on piRNA pathway and miRNA/siRNA (microRNA/small interfering RNA) pathway genes between teleosts and mammals showed an accelerated evolution of piRNA pathway genes in the teleost lineages, and positive selection on functional PAZ (Piwi/Ago/Zwille) and Tudor domains involved in the Piwi-piRNA/Tudor interaction, suggesting that the amino acid substitutions are adaptive to their functions in piRNA pathway in the teleost fish species. Notably five piRNA pathway genes evolved faster in the swamp eel, a kind of protogynous hermaphrodite fish, than the other teleosts, indicating a differential evolution of piRNA pathway between the swamp eel and other gonochoristic fishes. In addition, genome-wide analysis showed higher diversity of transposons in the teleost fish species compared with mammals. Our results suggest that rapidly evolved piRNA pathway in the teleost fish is likely to be involved in the adaption to transposon diversity.
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
Minhan
M
Yi
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
Feng
F
Chen
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
Majing
M
Luo
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
Yibin
Y
Cheng
Department of Zoology, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
Huabin
H
Zhao
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China hhcheng@whu.edu.cn rjzhou@whu.edu.cn.
Hanhua
H
Cheng
Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China hhcheng@whu.edu.cn rjzhou@whu.edu.cn.
Rongjia
R
Zhou
D000818:Animals; D004251:DNA Transposable Elements; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005399:Fishes / Q000235:genetics* / Q000378:metabolism; D016678:Genome; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism; D012641:Selection, Genetic; D016415:Sequence Alignment; D015398:Signal Transduction
D004251:DNA Transposable Elements; D029941:Fish Proteins; D034741:RNA, Small Interfering
evolution; positive selection; reproduction; teleost fish