Chromosome-scale and haplotype-resolved genome assembly of the autotetraploid Misgurnus anguillicaudatus.

In nature, diploids and tetraploids are two common types of polyploid evolution. Misgurnus anguillicaudatus (mud loach) is a remarkable fish species that exhibits both diploid and tetraploid forms. However, reconstructing the four haplotypes of its autotetraploid genome remains unresolved. Here, we generated the first haplotype-resolved, chromosome-level genome of autotetraploid M. anguillicaudatus with a size of 4.76 Gb, contig N50 of 6.78 Mb, and scaffold N50 of 44.11 Mb. We identified approximately 2.9 Gb (61.03% of genome) of repetitive sequences and predicted 91,485 protein-coding genes. Moreover, allelic gene expression levels indicated the absence of significant dominant haplotypes within the autotetraploid loach genome. This genome will provide a valuable biological model for unraveling the mechanisms of polyploid formation and evolution, adaptation to environmental changes, and benefit for aquaculture applications and biodiversity conservation.