Exploration of mtDNA control region sequences in Chinese Tibetan Mastiffs

Abstract

The control region of mitochondrial DNA (mtDNA) was obtained from 40 purebred Chinese Tibetan Mastiffs (TMs). Sequence structure and genetic diversity were analyzed, and a phylogenetic tree was constructed. The TM mtDNA control region was composed of ETAS (extended termination associated sequences), CD (a central domain) and CSBs (conserved sequenced blocks) and sequence length showed some diversity, which was mainly caused by the number of 10 nucleotide repeat units [5′-GTA CAC GT (G/A) C-3′] between CSB I and CSB II, which ranged from 27 to 35 among individuals. Seventy-five polymorphic sites were identified, which defined 37 haplotypes; the haplotype diversity was 0.990, and the nucleotide diversity was 1.201. Based on the control region sequences, Chinese TMs were divided into three categories, which were consistent with the origin and geographical classification of TMs. Phylogenetic analysis of 538-bp HVR-I sequences revealed that TMs were most closely related to Labrador Retrievers.

Keywords:

• Tibetan Mastiff
• mitochondrial control region
• hypervariable region
• genetic diversity

Acknowledgments

We thank Mallory Eckstut, PhD, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.

Disclosure statement

The authors declare that they have no conflict of interest in relation to this submission.

Additional information

Funding

This study was supported by the Natural Science Foundation of Jiangsu Province (grant # BK20141092).