Читать книгу Horse Genetics - Ernest Bailey - Страница 18

Today, two species of horse exist, the modern domestic horse (Equus caballus) and the Przewalski horse (Equus przewalskii). The two species are so similar that both are considered horses (Chapter 3 discusses all extant species of Equus), but they have so many phenotypic and genotypic differences that they are recognized as different species. Scientists have even been able to isolate DNA from equid bones preserved for thousands of years for comparison of ancient to modern horses (Orlando et al., 2013). Molecular genetic studies of DNA from modern horses and DNA isolated from bone fragments suggest that ancestors of domestic horses and Przewalski horses diverged 41,000–70,000 years ago (Schubert et al., 2014). That study reported evidence suggesting the existence of at least three different species of prehistoric horse, one identified as living in arctic regions (Siberia) and described as “ancient” (ANC), one leading to the modern domestic horse (DOM) and one leading to the modern Przewalski horse (PRZ). The ANC species went extinct sometime in the last 5000 years. The only horse species found today are the modern domestic horses and the Przewalski horse.