Blood Transcriptome Analysis of Semi-natural Population and Captive Population of Yangtze Finless Porpoise

Abstract: To compare and analyze the gene expression differences between semi-natural population and captive population of Yangtze finless porpoise (YFP, Neophocaena asiaeorientalis asiaeorientalis), and to clarify the influence of habitat on YFPs and its environmental adaptation mechanism, we performed transcriptome sequencing for blood tissues of YFPs collected from ex situ reserve and aquarium. Using RNA-seq we identified 6860 differentially expressed genes (DEGs), of which 6603 were up-regulated and 257 were down- regulated in the captive population. GO and KEGG enrichment analysis showed that the preferred genes in captive population were significantly correlated with glucose metabolism, amino acid metabolism and nervous system, while those in semi-natural population were significantly correlated with energy supply and biosynthesis. Further analysis showed that metabolism and hearing-related genes were significantly affected by habitat, and key metabolic genes such as HK, PFK, IDH and GLS and key hearing-related genes such as OTOA, OTOF, SLC38A1 and GABBR2 were discovered. The results suggest that the captive YFPs may improve the glucose metabolism ability by activating glycolysis/gluconeogenesis, TCA cycle, D-glutamine and D-glutamic acid, and inositol phosphate metabolism, while the semi-natural YFPs may meet higher energy requirements by improving amino acid metabolism of liver and muscle and oxidative phosphorylation. In addition, the habitat area may change the expression pattern of auditory-related genes by affecting the acoustic behavior of the YFPs and then affecting its auditory sensitivity. This study provides a new perspective for further exploring the adaptability of YFPs to various habitats, and provides a theoretical reference for further strengthening the protection practice of YFPs.