Molecular phylogeny of the Bactrian camel based on mitochondrial Cytochrome b gene sequences

The Bactrian camel is an important domesticated animal providing milk, meat, and other products in desert countries. In this study, 111 individuals representing 11 domestic Bactrian camel breeds from China, Mongolia, Russia, and one wild Bactrian camel group from Mongolia were selected for the preparation of mitochondrial DNA. The 1140-bp fragments of the cytochrome b gene (Cytb) were amplified by polymerase chain reaction and sequenced directly. Sequences of the 92 domestic and 19 wild Bactrian camel samples were analyzed with DNASTAR, and a phylogenic tree was constructed using MEGA. The analysis revealed sixteen haplotypes among the samples that were divided into two haplogroups: a domestic haplogroup (H1-H13, H15, and H16) and a wild haplogroup (H14). Haplotype diversity values were from 0.356 in the HosZogdort, to 0.889 in the Sunit Bactrian camel breed. The Sunit breed displayed the highest nucleotide diversity value (0.00115), and the HosZogdort breed had the lowest value (0.00031). All domestic Bactrian camels formed a single monophyletic lineage that is the sister group to wild Bactrian camels, a finding consistent with a single domestication event and independent maternal inheritance since domestication. In addition, the most common mitochondrial haplotypes (H1, H3, and H4) were shared between Chinese, Mongolian, and Russian domestic Bactrian camels, which indicated that there was no distinguishing geographic structure among the domestic breeds from these three regions. These findings provide important insights into patterns of relatedness among Bactrian camels from the Chinese, Mongolian, and Russian regions.