Document Type : Original Article
Authors
1
Department of Animal Science, Faculty of Agriculture, University of Aleppo, Aleppo, Syria.
2
Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad
Abstract
Mitochondrial DNA (mtDNA) sequencing, particularly of the control region, is a powerful tool for assessing genetic diversity and phylogenetic relationships due to its high mutation rate and maternal inheritance. Although several studies have examined mtDNA in Iranian sheep, they have often been limited by small sample sizes, and the haplogroup classification of native Iranian breeds remains unclear. This study provides a comprehensive phylogenetic analysis of 12 Iranian sheep breeds including Baluchi, Kaboudeh, Lori-Bakhtiari, Mehrabani, Dalagh, Ghezel, Iran Black, Kermani, Makouei, Sanjabi, Zel, and Moghani using mitochondrial control region sequencing. Five to ten blood samples per breed were collected, DNA was extracted via the guanidinium thiocyanate method, and a 1,400 bp fragment was amplified using specifically designed primers. Following PCR product purification and bidirectional Sanger sequencing, phylogenetic relationships were inferred using the UPGMA method in CLC Sequence Viewer v7.6. To contextualize the results, sequences were compared with control region sequences from global domestic sheep breeds and five major wild sheep haplotypes, A to E. The results showed that Baluchi, Iran Black, Moghani, Dalagh, Makouei, Sanjabi, Mehrabani, and Kaboudeh belong to haplogroup A, whereas Ghezel, Zel, Kermani, and Lori-Bakhtiari belong to haplogroup B. Notably, the Ghezel breed clusters closely with European breeds (Turkish Karayaca, Sakiz, Kivircik; Italian Gentile di Puglia and Bergamasca; German Merino) and the wild species Ovis vignei, native to Iran and the Middle East. In contrast, Baluchi, Iran Black, Mehrabani, and Kaboudeh group with breeds from Egypt (Sa'idi), Turkey (Herik), Pakistan (Damani), and Germany (Rhön sheep), as well as with Ovis ammon. The Zel and Dalagh breeds show high similarity to Iraqi breeds (Hamdani, Karadi), likely reflecting geographical proximity. Overall, the mitochondrial control region proved highly informative for estimating genetic distances among sheep breeds due to its relatively high mutation rate. This study represents the first comprehensive analysis of the mitochondrial control region in native Iranian sheep, and 11 consensus sequences have been deposited in NCBI GenBank (accession numbers MH699966–MH699973 and MH553568–MH553570). In conclusion, our study confirms that Iranian sheep possess a distinct but overlapping mitochondrial genetic structure with global populations, with haplogroup A dominance reflecting Iran's role in the Near Eastern domestication center, and the presence of haplogroup B in some breeds indicating historical gene flow. We recommend that future research expand sampling, employ full mitogenome sequencing, and integrate nuclear markers to further refine conservation priorities for Iran's invaluable ovine genetic resources.
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