Genome assembly and whole-genome resequencing study of Butuo Black sheep (Ovis aries)

Butuo Black sheep (BBS), an ancient indigenous Chinese breed, has co-evolved with the Yi people's semi-nomadic lifestyle and demonstrated exceptional adaptability to high-altitude migrations. However, a high-quality reference genome for BBS is still lacking. In this study, we established a high-quality chromosome-level genome assembly of BBS using PacBio HiFi sequencing. The final assembled genome size was approximately 2.95 Gb, with a contig N50 of 71.45 Mb and a scaffold N50 of 92.26 Mb. The genome assembly achieved a high Benchmarking Universal Single-Copy Orthologs (BUSCO) score of 95.9%, indicating its high completeness and quality. The de novo genome prediction revealed that repetitive sequences accounted for 47.74% of the genome, with long interspersed nuclear elements (LINEs) being the most abundant. Additionally, we present 50 BBS shotgun genomes sequenced using the Illumina HiSeq 2000 platform, with a mean coverage of 10.36×. The study generated approximately 1.2 terabytes of raw data, with 99.9% clean reads mapping successfully to the sheep reference genome at 99.6% coverage. This extensive dataset provides a valuable resource for studying genetic diversity and evolutionary patterns in BBS.