Genome refinement in Pacific bluefin tuna (Thunnus orientalis): chromosome-level assembly using hybrid linkage data

BACKGROUND: High-quality reference genomes are fundamental for selective breeding and genetic engineering to improve aquaculture productivity. Here, we report an improved chromosome-level genome assembly of Pacific bluefin tuna (Thunnus orientalis), a commercially valuable species consumed worldwide. By integrating genetic linkage information from interspecific hybrids of Euthynnus affinis and T. orientalis, we anchored and oriented T. orientalis scaffolds into 24 pseudochromosomes. RESULTS: The updated assembly achieved a scaffold N50 of 34.19 Mb, representing a notable improvement from 13.3 Mb, and contained 22,640 predicted protein-coding genes. CONCLUSIONS: This resource provides a robust genomic foundation for future genetic and genomic studies to advance the selective breeding of T. orientalis in aquaculture.