Investigation of relationship between mtDNA D-loop among Turkish and Pakistani Sheep Breeds

Sheep (Ovis aries) is the first domesticated animal which plays an important role in human life as it spread all over the world. Evidence suggests that today's modern sheep descended from Asian Mouflon (Ovis orientalis) in the Fertile Crescent region of southwest Asia 8 – 11 thousand years ago. The genetic diversity among domestic sheep breeds is important and their reduction or loss will have economic, ecological and scientific impacts. Genetic differences both within and between sheep breeds provide information about intra-breed management practices, while revealing the effect of different genotypes on the breed. In this research, genetic relationships among six sheep breeds from Turkey, namely Akkaraman, Morkaraman, Karayaka, Pırlak, Sakız, Kıvırcık and seven sheep breeds from Pakistan, namely Thalli, Sipli, Lohi, Kajli, Buchi, Salt Range and Pak Karakul were investigated. A total of 1255 bp of the sheep mitochondrial DNA control region (mtDNA D-Loop) was amplified by PCR, but 1077 bp portion was used for statistical analysis. Among the domestic sheep breeds of Turkey, the least genetic differentiation was observed in Sakız breed (1%), on the other hand the highest genetic differentiation was observed in Morkaraman breed (3.1%). In Pakistani sheep breeds, the least genetic differentiation was found in Sipli breed (0.9%) and the highest genetic differentiation was found in Salt Range breed (2%). The numbers of polymorphic regions in Turkey and Pakistan sheep breeds were calculated as 230 and 203 respectively. Turkish sheep breeds (0.0191) have higher nucleotide diversity than Pakistani sheep breeds (0.0139). According to genetic distance values, 99% of Turkish sheep breeds are in Haplogroup B, while 99% of Pakistani sheep breeds are in Haplogroup A. The highest genetic similarity among Turkish sheep breeds was found between Sakız and Kıvırcık (98.4%) and the lowest between Morkaraman and Pırlak (97%). In Pakistani sheep breeds, the highest vi genetic similarity was found between Sipli and Lohi (98.4%), while the lowest was found between Salt Range and Thalli and Salt Range and Kajli (98%). According to Maximum Parsimony and Network analyses, some of the animals belonging to Akkaraman and Morkaraman breeds are in Haplogroup A, while most of the animals from Turkish sheep breeds have Haplogroup B. A small number of Morkaraman and Karayaka animals were found in Haplogroup C, while only one Karayaka animal was identified in Haplogroup E. It is noteworthy that the cluster formed by the Wild sheep (Ovis aries musimon) has only one animal from Kıvırcık and one from Pırlak. According to Maximum Parsimony and Network analyses, most Pakistani sheep were included in Haplogroup A. However, Haplogroup B was observed in a small number of animals from Salt Range and Pak Karakul breeds. It is noteworthy that no animals were found in Haplogroups D and E, while two heads of Kajli sheep are found in Haplogroup C. As a result, the high frequency of Haplogroup B in Turkish domestic sheep breeds indicates that the origin of these breeds may be from European wild sheep. However, the fact that Haplogroups A and C are also found in high numbers indicates that the migration of Turks from Central Asia has an effect on the genetic structure of Turkey's domestic sheep. The fact that Pakistani domestic sheep breeds have Haplogroup A indicates that they were domesticated from Asian wild sheep. However, Haplogroup B, which is seen in some breeds, also indicates that there were crosses over time to time with sheep domesticated from European wild sheep. It would be beneficial to use mt-DNA and genomic DNA together to understand the genetic relationship between Asian and European sheep breeds as well as to investigate West and Central Asian sheep breeds and the sheep breeds in Turkey and Pakistan.