Comparative mitogenomic analysis of Chinese cavefish Triplophysa (Cypriniformes: Nemacheilidae): novel gene tandem duplication and evolutionary implications.

IF 3.5 2区 生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY
Shuang Song, Jianhan Cao, Hongmei Xiang, Zhixiao Liu, Wansheng Jiang
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引用次数: 0

Abstract

Background: Cavefish exhibit significant morphological changes that result in trade-offs in metabolic requirements and energy utilization in perpetual darkness. As cellular "powerhouses", mitochondria play crucial roles in energy metabolism, suggesting that mitochondrial genes have likely experienced selective pressures during cavefish evolution.

Results: This study presents the first assembly of the complete mitogenome of Triplophysa yangi, a typical cavefish species in China. The mitogenome is 17,068 bp long, marking the longest recorded for the genus Triplophysa, and includes 13 protein-coding genes (PCGs), 2 rRNAs, 25 tRNAs, and a noncoding control region. An ~ 500 bp insertion between ND2 and WANCY regions was observed, comprising a large intact tandem repeat unit (A'-N'-OL'-C') flanked by two unannotated sequences (U1/U2). The evolutionary origin of this repeat unit may involve either in situ duplication events with subsequent functional divergence-where neofunctionalization, subfunctionalization, or pseudogenization drove differential mutation rates between paralogs-or alternatively, horizontal acquisition from exogenous genetic material that became functionally integrated into the ancestral T. yangi mitogenome through co-option mechanisms. Phylogenetic analyses revealed two major clades within Triplophysa-epigean and hypogean lineages-consistent with previous classifications, while cave-restricted species exhibited signs of parallel evolution within the hypogean lineage. Selective pressure analysis indicated that the hypogean lineage (cave-dwelling groups, II & III) have a significantly increased ratio of nonsynonymous to synonymous substitution rates (ω) compared to the epigean lineage (surface-dwelling group, I), suggesting a combination of adaptive selection and relaxed functional constraints in cave-dwelling species.

Conclusions: The duplication of tRNAs in T. yangi and the potential positive selection sites identified in Triplophysa cavefish further indicated adaptive evolution in mitochondrial PCGs in response to extreme subterranean conditions.

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来源期刊
BMC Genomics
BMC Genomics 生物-生物工程与应用微生物
CiteScore
7.40
自引率
4.50%
发文量
769
审稿时长
6.4 months
期刊介绍: BMC Genomics is an open access, peer-reviewed journal that considers articles on all aspects of genome-scale analysis, functional genomics, and proteomics. BMC Genomics is part of the BMC series which publishes subject-specific journals focused on the needs of individual research communities across all areas of biology and medicine. We offer an efficient, fair and friendly peer review service, and are committed to publishing all sound science, provided that there is some advance in knowledge presented by the work.
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