Chromosome-level genome assemblies of five Sinocyclocheilus species

Sinocyclocheilus , a genus of tetraploid fishes, is endemic to the karst regions of Southwest China. All species within this genus are classified as second-class national protected species due to their unique and fragile habitat. However, absence of high-quality genomic resources has hindered various research efforts to elucidate their phylogenetic relationships and the origin of polyploidy. To address these academic challenges, we at first constructed a high-quality genome assembly for the most abundant representative, golden-line barbel ( Sinocyclocheilus grahami ), by integration of PacBio long-read and Hi-C sequencing technologies. The final scaffold-level genome assembly of S. grahami is 1.6 Gb in length, with a scaffold N50 up to 30.7 Mb. A total of 42,205 protein-coding genes were annotated. Subsequently, 93.1% of the assembled genome sequences (about 1.5 Gb) and 93.8% of the total predicted genes were successfully anchored onto 48 chromosomes. Furthermore, we obtained chromosome-level genome assemblies for four other Sinocyclocheilus species (including S. anophthalmus, S. maitianheensis, S. anshuiensis , and S. rhinocerous ) based on homologous comparison. These genomic data we present in this study provide valuable genetic resources for in-depth investigation on cave adaptation and improvement of economic values and conservation of diverse Sinocyclocheilus fishes.