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

• Published in: iScience
• Main Authors: Zhang, Jie, Qi, Jiwei, Shi, Fanglei, Pan, Huijuan, Liu, Meng, Tian, Ran, Geng, Yuepan, Li, Huaying, Qu, Yujie, Chen, Jinping, Seim, Inge, Li, Ming
• Format: Text
• Language: English
• Published: Elsevier 2020
• Subjects: Article; Icefish
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327861/; http://www.ncbi.nlm.nih.gov/pubmed/32593955; https://doi.org/10.1016/j.isci.2020.101267

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.