The new chimeric chiron genes evolved essential roles in zebrafish embryonic development by regulating NAD+ levels  

作　　者：Chengchi Fang Xiaoni Gan Chengjun Zhang Shunping He 

机构地区：[1]The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences,Institute of Hydrobiology,Chinese Academy of Sciences,Wuhan 430072,China [2]Kunming Institute of Botany,Chinese Academy of Science,Kunming 650201,China [3]University of Chinese Academy of Sciences,Beijing 100039,China [4]Center for Excellence in Animal Evolution and Genetics,Chinese Academy of Sciences,Kunming 650223,China [5]Huazhong Agricultural University,Wuhan 430070,China

出　　处：《Science China(Life Sciences)》2021年第11期1929-1948,共20页中国科学（生命科学英文版）

基　　金：This project is supported by the Pilot projects(XDB13020100);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB31000000);the National Natural Science Foundation of China(NSFC,31601859).

摘　　要：The origination of new genes is important for generating genetic novelties for adaptive evolution and biological diversity.However, their potential roles in embryonic development, evolutionary processes into ancient networks, and contributions to adaptive evolution remain poorly investigated. Here, we identified a novel chimeric gene family, the chiron family, and explored its genetic basis and functional evolution underlying the adaptive evolution of Danioninae fishes. The ancestral chiron gene originated through retroposition of nampt in Danioninae 48–54 million years ago(Mya) and expanded into five duplicates(chiron1–5) in zebrafish 1–4 Mya. The chiron genes(chirons) likely originated in embryonic development and gradually extended their expression in the testis. Functional experiments showed that chirons were essential for zebrafish embryo development. By integrating into the NAD^(+) synthesis pathway, chirons could directly catalyze the NAD^(+) rate-limiting reaction and probably impact two energy metabolism genes(nmnat 1 and naprt) to be under positive selection in Danioninae fishes. Together,these results mainly demonstrated that the origin of new chimeric chiron genes may be involved in adaptive evolution by integrating and impacting the NAD^(+) biosynthetic pathway. This coevolution may contribute to the physiological adaptation of Danioninae fishes to widespread and varied biomes in Southeast Asian.

关 键 词：new chimeric genes essential function NAD^(+)rate-limiting enzyme coevolution 

分 类 号：Q344[生物学—遗传学]