Comparative transcriptomics reveals the molecular genetic basis of pigmentation loss in Sinocyclocheilus cavefishes. Issue 24 (19th November 2020)

• Record Type: Journal Article
• Authors: Li, Chunqing; Chen, Hongyu; Zhao, Yinchen; Chen, Shanyuan; Xiao, Heng
• Is Part Of: Ecology and evolution. Volume 10:Issue 24(2020)
• Page Start: 14256
• Page End: 14271
• Publication Date: 2020-11-19
• Subjects: cavefish -- comparative transcriptomics -- pigmentation -- Sinocyclocheilus -- troglomorphic trait; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.7024
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract: Cave‐dwelling animals evolve distinct troglomorphic traits, such as loss of eyes, skin pigmentation, and augmentation of senses following long‐term adaptation to perpetual darkness. However, the molecular genetic mechanisms underlying these phenotypic variations remain unclear. In this study, we conducted comparative histology and comparative transcriptomics study of the skin of eight Sinocyclocheilus species (Cypriniformes: Cyprinidae) that included surface‐ and cave‐dwelling species. We analyzed four surface and four cavefish species by using next‐generation sequencing, and a total of 802, 798, 907 clean reads were generated and assembled into 505, 495, 009 transcripts, which contributed to 1, 037, 334 unigenes. Bioinformatic comparisons revealed 10, 629 and 6, 442 significantly differentially expressed unigenes between four different surface‐cave fish groups. Further, tens of differentially expressed genes (DEGs) potentially related to skin pigmentation were identified. Most of these DEGs (including GNAQ, PKA, NRAS, and p38 ) are downregulated in cavefish species. They are involved in key signaling pathways of pigment synthesis, such as the melanogenesis, Wnt, and MAPK pathways. This trend of downregulation was confirmed through qPCR experiments. This study will deepen our understanding of the formation of troglomorphic traits in cavefishes. Abstract : We conducted a comparative histology and comparative transcriptomics study on the skin of eight Sinocyclocheilus species, including four surface and four cavefish species. The result suggests that these differentially expressed genes (DEGs) may be responsible for pigmentation loss in the Sinocyclocheilus cavefish species.