Telomere-to-telomere Genome Assembly of Equus kiang (Tibetan wild donkey)

The Tibetan wild donkey (Equus kiang) is an endemic equid species inhabiting the Qinghai-Tibet Plateau, exhibiting remarkable chromosomal diversity within the Equus genus. Here we present a chromosome-level, telomere-to-telomere genome assembly for E. kiang generated using Illumina short reads, PacBio HiFi long reads, and Hi-C sequencing data. The final assembly spans 4.02 Gb and comprises 27 pseudochromosomes. Specifically, 8 chromosomes are gapless, 8 chromosomes have one gap, 7 chromosomes have 2-4 gaps, and the remaining 4 chromosomes have five or more gaps. Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis indicated 96.7% completeness, demonstrating high assembly quality. Comparative genome collinearity with the domestic horse (E. caballus) showed that 11 E. kiang chromosomes displayed a simple one-to-one chromosome-scale correspondence. We further characterized genomic features associated with these regions, including the enrichment of tandem repeats near recombination breakpoints. This high-quality genome assembly provides a foundational resource for studies of chromosome evolution, speciation, and genomic architecture in Equus and other mammals.