Przewalksi’s horse can hybridize with domestic horses to produce fertile offspring, even though they are distinct populations.
Przewalski’s horse (Equus ferus przewalskii) can hybridize with domestic horses (Equus ferus caballus) to produce fertile offspring.
Studies of the genetic differences between Przewalski’s and domestic horses have indicated very little genetic distinction between them. Only four alleles at four separate serological marker loci have been identified as specific to Przewalski’s horse. The vast majority of blood protein variants are present in both Przewalski’s and domestic horses and even the fastest evolving DNA region known in mammals, the mitochondrial DNA control region, does not show significant differences between the two types of horse. Thus, it is clear that Przewalski’s and domestic horses are very closely related and have in the past interbred, but the fixed chromosomal number difference between them indicates that they are distinct populations. A variety of molecular studies support their phylogenetic relationship as sister taxa diverging between 150,000 and 250,000 years ago.
• Image | © Smithsonian’s National Zoo, Some Rights Reserved, (CC BY-NC-ND 2.0)
• Sources | Bowling & Ryder, 1987; Côté, Viel, & Bienzle, 2013; Goto, et al., 2011; Ishida, et al., 1995; King, Boyd, Zimmermann, & Kendall, 2015; Oakenfull, Lim, & Ryder, 2000; Oakenfull & Ryder, 1998; Ryder, Epel, & Benirschke, 1978, Steiner, Mitelberg, Tursi, & Ryder, 2012; Steiner & Ryder, 2011; Trommerhausen-Smith, Ryder, & Suzuki, 1979