Comparative Genomics of Mongolian Purebred and Hybrid Horses: Conserving an Important Breed

Abstract

The Mongolian horse has been primarily under natural selection since its ancestral time due to the almost wild existence it lives in Mongolia. This has enabled the Mongolian horse to retain a high level of ancestral diversity compared to other horse breeds that have been bred selectively for certain traits. However, their high level of diversity and breed identity is being put in danger as Mongolian horses are being crossbred to western breeds imported from Europe and Eastern Russia. In addition to this, a movement has started within Mongolia to create a Mongolian Horse Breed Registry. Unfortunately there are no precautions currently in place to ensure that only purebred Mongolian horses are allowed into this new registry. Therefore differences between the genomes of the Mongolian purebreds and Mongolian crossbreds were examined in order to develop a test that will identify which individuals should be allowed into the newly proposed registry. Currently, three microsatellite alleles found on separate loci have been identified in the crossbreeds but not the purebreds. These three alleles could possibly be used to distinguish between the purebreds and crossbreds; however more horse samples will have to be processed before this can be determined. The overall diversity within the Mongolian breed was also analyzed and compared to diversity found within other breeds. This data shows the Mongolian horse to have a higher than average heterozygosity and number of alleles.