Genome assembly at chromosome level and evolutionary analysis of Coregonus ussurinsis Berg

The Coregonus ussurinsis Berg (C. ussurinsis) is widely distributed in cold waters above 45° north latitude and favoured by consumers because of its delicate and delicious meat. However, it is included in the list of endangered animals due to the sharp decrease in its population by overfishing. The lack of genomic information has seriously hindered the evolution and genetic research process of C. ussurinsis. Therefore, it is urgent to assemble a high-quality reference genome to promote the genetic breeding research of C. ussurinsis. Here, we used PicBio sequencing and Hi-C assembly technology to assemble and construct the reference chromosome-level genome of C. ussurinsis. The sequence length was 2,627.19 Mb with a contig N50 length of 4.27 Mb. Then 3,109 contigs were assembled into scaffolds, resulting in a genome assembly with 40 chromosomes and a scaffold N50 length of 62.20 Mb, and the size of the genome was 2.51 Gb, and the integrity was more than 95% by BUSCO test. In addition, a total of 43,320 protein-coding genes were annotated and repetitive elements accounted for 67.37% of the genome. Phylogenetic analysis showed that the divergence between the C. ussurinsis and Coregonus sp. Balchen (the Swiss alpine whitefish) occurred 18 million years ago, and the divergence time between the C. ussurinsis and other 10 species of Salmonidae, including rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar), was 49.1 million to 63.7 million years ago. The C. ussurinsis had the most distant relative with the sterlet (Acipenser ruthenus) and diverged as early as 300 million years ago. This chromosome-level genome provides reference data for further study of molecular breeding of the C. ussurinsis.