Abstract
In this study, a phylogenetic analysis was conducted to determine the genetic diversity of the Kazakh fat-tailed coarse-wool sheep breed raised in Kazakhstan using SNP polymorphisms of the mitochondrial DNA (mtDNA) d-loop region consisting of 840 base pairs (bp). A total of 80 Kazakh fat-tailed coarse-wool sheep were initially sampled from two breeding farms in Kazakhstan. Following DNA extraction, PCR amplification, and sequencing, 10 samples were successfully sequenced for the mitochondrial DNA (mtDNA) D-loop region. For comparative phylogenetic analysis, these 10 newly generated sequences were combined with 15 reference sequences retrieved from the NCBI GenBank database, resulting in a final dataset of 25 sequences. DNA molecules were extracted from peripheral blood samples, and polymerase chain reaction (PCR) amplification was performed. Sequencing analysis of the amplified products revealed nucleotide compositions of 31.46% adenine, 36.19% thymine, 16.42% guanine, and 15.93% cytosine. The obtained sequences were compared with available nucleotide sequences of domestic sheep and wild mouflon breeds from the NCBI database. Phylogenetic tree analysis conducted using the MEGA X software demonstrated that the Kazakh fat-tailed coarse-wool sheep formed a distinct cluster with a 98–100% genetic similarity, indicating a unique genetic diversity and confirming its status as an autochthonous sheep breed. Furthermore, the Kazakh fat-tailed coarse-wool sheep showed a close genetic relationship with Mongolian, Tibetan, and Gissar sheep breeds. In contrast, European sheep breeds were positioned at a greater genetic distance in the phylogenetic tree, suggesting that they belong to different evolutionary lineages.