The nuclear genetic diversity of Turkish native horse breeds and its conservation implications

Abstract

Anatolia has been home to many ancient civilizations. More importantly, Southeast Anatolia was part of the place, called the Fertile Crescent, where hunter gatherers established permanent settlements and domesticated some plant and animal species. The period of initial domestication and shift from hunting-gathering to farming and agriculture has not been well defined, yet. However, it is well known that Anatolia was associated with the domestication of some of the livestock animals; goat, sheep and pig. Hence, Anatolian populations of many livestock species might contain genetic evidence to fill the gaps and unravel their domestication stories. One of these species is the horse (Equus caballus). Due to rapid mechanization in Turkish agriculture, the native Turkish horses have been in a decline, lately. However, the use of horse power in field cultivation and transportation is still a necessity. The genetic characterization of the present native breeds, and assessing the prioritization of the breeds are the first steps to preserve the present genetic diversity, to meet the demands of future breeding programs and to develop conservation strategies. In this study, a total of 425 horse samples were genotyped at 21 microsatellite loci. These samples included five Anatolian domestic breeds of known phenotypes (Hinis, Canik, Malakan, Cukurova horses and Ayvacık Pony) and two Anatolian horse samples without defined phenotypic characteristics (Erzurum and East Anatolian horses), and two foreign breeds (English and Arabian horses), for comparison. The present genetic variation measured by heterozygosity and number of alleles revealed high diversity in Anatolian horse breeds. Factorial Correspondence Analysis detected some level of population differentiation between breeds, though was not significant except for Ayvacık Pony. The Principal Component Analysis supported the FCA results; whereas, Structure analysis and Neighbour Joining tree could not make a clear differentiation within the Anatolian breeds. The analyses also suggested a unidirectional gene flow from the Arabian horses into the Anatolian breeds. The results indicated that stronger measures should be undertaken to conserve the genetic identity of the Anatolian breeds, which have already been compromised by the lack of clear breeding strategies.