Genetic Composition and Evaluation of the Status of a Non-descript Indigenous Horse Population From Greece, the Macedonian Pacer

Abstract

Characterization of indigenous domestic animal breeds is of high importance in the sense of conservation and genetic improvement. There are six registered indigenous Greek horse breeds, defined by geographic orientation, as well as a few non-descript ones. Among the latter, the Macedonian pacer population is the most featured one, exhibiting the specific gaiting ability to pace. This study constitutes the first genetic investigation of the Macedonian pacer horses, in an effort to examine the validity of their inclusion in the herdbook as a distinct breed. To achieve this goal, we analyzed the DMRT3 gene, which has been associated with the ability to pace, as well as the mitochondrial cyt b gene, to estimate the genetic relationships with other breeds. Analysis of the DMRT3 gene revealed a very high frequency (0.988) of the “gait keeper” allelic mutation. Genetic differentiation of the Macedonian pacer horses based on cyt b sequencing was in almost all pairwise comparisons significant and in equal or greater levels than in pairs of the rest Greek breeds, with Fst ranging from 0 to 0.355. Haplotype and nucleotide diversity in the Macedonian pacer population were 0.917 and 0.0044, respectively. Phylogenetic analysis resulted in low genetic distances supported by not significant values that indicated slight genetic divergence among different breeds. Overall, the fact that Macedonian horses exhibit a particular phenotypic character of locomotion, transmitted to the next generations in combination with the significant levels of genetic differentiation, are considered valuable data toward their recognition and official registration.