# A telomere-to-telomere gapless genome assembly of the Tibetan wild ass (Equus kiang)

## TL;DR

Scientists created a complete genome assembly of the Tibetan wild ass, a high-altitude species, to study its genetic adaptations.

## Contribution

The first telomere-to-telomere gapless genome assembly of the Tibetan wild ass is presented.

## Key findings

- The genome assembly is 2.49 Gb with 99.94% BUSCO completeness and a contig N50 of 107.02 Mb.
- The assembly includes all 54 telomeres and 27 centromeres across autosomes and sex chromosomes.
- Genome annotation identified 24,005 protein-coding genes and 36.52% repetitive sequences.

## Abstract

As a First-Class Protected species in China, the Tibetan wild ass (Equus kiang) is endemic to the Qinghai-Tibet Plateau and exhibits remarkable adaptation to extreme high-altitude environments characterized by low oxygen, cold temperatures, and high UV radiation. To explore its genetic basis and evolutionary adaptations, we generated the first telomere-to-telomere (T2T) gapless genome using an integrated sequencing strategy that combined PacBio HiFi, ultra-long Oxford Nanopore (ONT), Hi-C, and BGI short-read technologies. The resulting 2.49 Gb assembly achieved a contig N50 of 107.02 Mb, comprising all 54 telomeres and 27 centromeres across 25 pairs of autosomes and the X/Y chromosomes, and reached 99.94% BUSCO completeness. Genome annotation predicted 907 Mb of repetitive sequences (36.52% of the genome) and 24,005 protein-coding genes. Comparative and technical analyses confirmed high assembly continuity, completeness, and accuracy, with a consensus quality value (QV) of 64.73, providing a robust genomic reference for understanding the evolutionary mechanisms and adaptive traits of this iconic high-altitude ungulate.