High-quality genome assembly of Urial reveals key genes in body length reduction during sheep domestication
Wild sheep possess remarkable adaptive traits, making them invaluable genetic resources for improving domestic sheep breeds. Urial (Ovis vignei), an ancestral species of domestic sheep, has a body size approximately twice that of its domesticated counterparts. However, the absence of a high-quality genome assembly for Urial has limited our understanding of its domestication and adaptive traits. We present the first high-quality genome assembly of Urial, generated using Nanopore and Illumina sequencing technologies. The genome spans 2.57 Gb with a contig N50 of 28.88 Mb. We identified 735 expanding gene families and 113,382 structural variations. By analyzing the expanded gene families alongside structural variations, we identified nine potential functional variations. A zebrafish model study indicated that the Aldehyde Dehydrogenase 1A1 (ALDH1A1) gene plays a role in regulating vertebrate body length. Our findings provide insights into the genetic basis of the reduced body length observed in domestic sheep relative to their wild ancestors. This high-quality genome of wild sheep provides a valuable resource and a new perspective for comparative genetic and functional studies on sheep domestication.