Assessment of genetic diversity and differentiation among four indigenous Turkish sheep breeds using microsatellites.

Conservation and breeding programmes of livestock species depend on determination of genetic diversity. Today in livestock species, microsatellite markers are commonly used to reveal population structure and genetic diversity in both breeds and varieties. In this study, population structure, genetic diversity, and differentiation among four native Turkish sheep breeds including Güney Karaman, Kangal, Norduz, and Karakas were assessed by using 21 microsatellite loci. By genotyping 120 individuals belonging to four sheep breeds, a total of 275 different alleles, 37 of which were private alleles, were observed across all loci. The mean number of alleles per breed ranged from 7.28 (Güney Karaman) to 8.09 (Karakas), while allelic richness ranged from 7.22 (Güney Karaman) to 7.87 (Karakas). Mean observed heterozygosity varied from 0.60 (Kangal) to 0.66 (Norduz and Karakas). The lowest pairwise value (0.084) was between Kangal and Karakas populations, while the highest pairwise value (0.142) was between Norduz and Karakas populations. Polymorphic information content (PIC) values, ranging from 0.71 (ETH10) to 0.91 (OarFCB304), were highly polymorphic (PIC   0.5) and informative in studied populations. In the present study, the results of phylogenetic analysis were of importance, since all studied populations have been accepted as Akkaraman varieties till today. However, factorial correspondence and structure analysis, pairwise values, and an unweighted pair group method with arithmetic mean analysis (UPGMA) dendrogram revealed that Güney Karaman and Norduz populations have became genetically different from the Akkaraman breed due being raised in different parts of Turkey under different climatic conditions together with their breeding practices. Therefore, we recommend that more comprehensive molecular studies should be conducted to clarify genetic differentiation of Akkaraman sheep varieties.