Insights into the Evolution of Neoteny from the Genome of the Asian Icefish Protosalanx chinensis

• Published in: iScience
• Main Authors: Jie Zhang, Jiwei Qi, Fanglei Shi, Huijuan Pan, Meng Liu, Ran Tian, Yuepan Geng, Huaying Li, Yujie Qu, Jinping Chen, Inge Seim, Ming Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2020
• Subjects: Biological Sciences; Evolutionary Biology; Genomics; Science; Q; Icefish
• Online Access: https://doi.org/10.1016/j.isci.2020.101267; https://doaj.org/article/bcf6c70aaf7a4e3f9a8904933e9413ea

Summary: Salangids, known as Asian icefishes, represent a peculiar radiation within the bony fish order Protacanthopterygii where adult fish retain larval characteristics such as transparent and miniaturized bodies and a cartilaginous endoskeleton into adulthood. Here, we report a de novo genome of Protosalanx chinensis, the most widely distributed salangid lineage. The P. chinensis genome assembly is more contiguous and complete than a previous assembly. We estimate that P. chinensis, salmons, trouts, and pikes diverged from a common ancestor 185 million years ago. A juxtaposition with other fish genomes revealed loss of the genes encoding ectodysplasin-A receptor (EDAR), SCPP1, and four Hox proteins and likely lack of canonical fibroblast growth factor 5 (FGF5) function. We also report genomic variations of P. chinensis possibly reflecting the immune system repertoire of a species with a larval phenotype in sexually mature individuals. The new Asian icefish reference genome provides a solid foundation for future studies.