Near telomere-to-telomere genome assembly of the stone loach (Traccatichthys pulcher)

Traccatichthys pulcher is an ornamental loach species recognized for its vibrant body coloration, characteristic black dorsal fin margin, and iridescent green lateral stripes. To advance genomic research on this species, a high-quality, near telomere-to-telomere (T2T) genome assembly was generated using PacBio HiFi, ONT ultra-long, and Hi-C sequencing technologies. The resulting haplotype-resolved assembly spanned approximately 623.68 Mb, with a contig N50 of 22.9 Mb, and was anchored onto 24 chromosomes. Telomeric sequences were detected at both ends of eight chromosomes and at one end of 13 chromosomes. Twenty-three chromosomes were entirely gapless, while a single gap was identified in the remaining chromosome. The assembly contained 119.1 Mb of repetitive elements, and 23 967 protein-coding genes were annotated. BUSCO analysis indicated high completeness, with 98.6% of conserved genes recovered. This high-quality, near T2T genome assembly offers a valuable and robust genetic resource for investigating molecular mechanisms, evolutionary processes, conservation biology, and selective breeding of T. pulcher.