Comparative mitochondrial genomics of the Peruvian Creole sheep (Ovis aries)

The genetics of Peruvian Creole sheep (PCS) remains an understudied aspect of South American livestock genetics, even though this zoogenetic resource represents economic and cultural importance. This study analyzes the complete mitochondrial genome of five Peruvian Creole sheep (Ovis aries) individuals to assess their genetic variability and phylogenetic relationships. The mitochondrial genome exhibits a length of 16,617 base pairs (bp) with a guanine-cytosine (GC) content of 39%, encoding 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. Codon usage bias analysis reveals a marked preference for specific codons, particularly in Arginine (Arg), Serine (Ser), and Threonine (Thr), suggesting the influence of mutational pressure on mitochondrial gene evolution. Phylogenetic analysis places the PCS individuals within Clade III, alongside sheep breeds from Russia, Brazil, and New Zealand, but without forming a monophyletic group. The absence of monophyly suggests multiple historical introduction events and potential gene flow with different ovine populations, paralleling patterns observed in Mediterranean and African sheep breeds. The phylogenetic relationship of Peruvian Creole sheep with Brazilian and Chinese lineages highlights the complexity of their genetic background, indicating potential admixture and historical introgression. These findings underscore the need for further genomic research to clarify Peruvian Creole sheep's evolutionary history and support conservation efforts of their zoogenetic resources.