ABSTRACT
Aim: Cytochrome b (Cyt-b) regions of mtDNA have received more attention due to their role in the genetic diversity and phylogenetic studies in different livestock. By using Cytochrome b sequencing, we aimed to clarify the genetic affinities and phylogeny of six Egyptian sheep breeds. Methodology: The genomic DNA was extracted and the specific primers were used for conventional PCR amplification of the Cytochrome b region of mtDNA (1134-bp) in sheep. The alignment of sequences was done to identify the sequence variations and polymorphic sites in the amplified fragments. Results: The results showed the presence of 39 polymorphic sites leading to the formation of 29 haplotypes (accession numbers: MG407500 - MG407528) with total haplotype diversity 0.814 and nucleotide diversity 0.00359. The lowest genetic distance was observed between Rahmani and Saidi while the highest distance was observed between Ossimi and Sohagi. The sequences of 111 analyzed samples were aligned with reference sequences of different haplogroups; A, B, C, D and E. The result showed that 86 out of 111 tested animals cluster with haplogroup B (77.48%), whereas 12 tested animals cluster with each of both haplogroups A and C (10.81%) and one animal belongs to haplogroup E (0.90%) with the absence of haplogroup D. Conclusion: Cytochrome b regions of mtDNA have an important role in the genetic diversity and phylogenetic studies in farm animals as well as many other mammalian species.