Whole genome sequencing and de novo genome assembly of the Kazakh native horse Zhabe

Abstract

The horse (Equus caballus) is a domesticated animal with great significance in human civilization and history, having played a crucial role in transportation, agriculture, and warfare. Over millennia, intentional breeding has resulted in the creation of approximately 500 distinct horse breeds, each selected for specific performance qualities, appearance, and behavior (Petersen et al., 2013). The earliest evidence of horse domestication dates back to the Eneolithic Botai culture (3500 BCE) in prehistoric Northern Kazakhstan, where horses continue to hold cultural significance (Outram et al., 2009; Levine, 1999; Sarbassova, 2015). Although domestication in Botai occurred independently of the main domestication path, horses have been an essential aspect of steppe pastoralism in the region of modern Kazakhstan since the Bronze Age (Kyselý and Peške, 2022; Frachetti and Benecke, 2009; Outram et al., 2012). As a result, traditional selection over hundreds and thousands of years has shaped the Kazakh horse breed (Kabylbekova et al., 2024).

Zhabe is an intrabreed type of Kazakh horse that originated in Western Kazakhstan and is currently used throughout the country (Figure 1A). This type is known for its strong, slightly rough constitution and high endurance. Horses of this type are characterized by a coarse head, a short fleshy neck, a wide and deep body, a broad back, a muscular croup, and strong, bony legs. They also have a thick, long mane and tail, short fetlocks on the legs, and dense skin. Their colors are typically bay or dark red, but can also be mousey, gray, or black (Dmitriev and Ėrnst, 1989). In state farm conditions, Kazakh horses, including Zhabe, have been selectively bred for increased size and weight. They are well-adapted to traditional Kazakh methods of seasonal pasturing and are bred in herds, even inharsh winter climatic conditions, to produce working horses, meat, and milk (Omarov et al., 2019).