2009, Vol.22, No.1

Anatomy & Biological Anthropology 2023 KCI Impact Factor : 0.33

pISSN : 2671-5651 / eISSN : 2671-566X
https://journal.kci.go.kr/aba

The aim of this study is to identify the species characteristics of the dog mastication compared to the human by analyzing 8 landmarks on the heads from seven beagle dogs. The masticatory unit of the dog was relatively located posterior than the human. The predominance of horizontally-oriented fibers of the temporalis of the dog was shown in spite of vertical mandibular movement. The biomechanics of the coronoid process and the temporalis of the dog revealed but not superiorly-elevating like the human backward rotating the coronoid process. The masseter was also obliquely -oriented and the temporalis was observed in distinct two-layers. In the dogs, the higher coronoid process compared to the condyle was observed; the vertical difference of them was larger than human. The temporalis performs stronger action than masseter and related with marked horizontal action of the temporalis. These morphologies indicated that the mastication of the dog needs strengthened horizontal stability and it was taken by the cervical muscles attached backwardly to the skull. Thickened temporalis is adapted in feeding. The dentition of dog was longer and farther from the condyle and the pterygoid muscles were not well-developed than human, indicated unfavourable lateral movement. These findings were consistent with evolutionary tendency, feeding without hands and narrow skull.

As characterization of mitochondrial DNA (mtDNA) shows maternal inheritance and exists as more than thousands copies per cell, it is widely used for population genetics and forensic scientific field. However, mitochondrial DNA study has difficulties because heteroplasmy of mtDNA is being reported from coding and control region. In this study, we have analyzed 200 samples to examine heteroplasmy in mitochondrial DNA of Korean and Mongolian. The control region and coding region in mtDNA of blood from Koreans and Mongolians were analyzed with PCR amplication and sequencing. As a result, several heteroplasmy was observed from total 10 positions including 5 positions in coding region and 5 positions in control region, respectively. Moreover, it showed more than one heteroplasmy in coding region from 6 samples in Korean and 17 samples in Mongolian. Interestingly, heteroplasmy at 5178 position was shown in 6 samples among 23 samples. Considering that the position is important for deciding haplogroup D, we suggest that additional analysis on 4883 position needs for correct haplogrouping. Beside, we also found heteroplasmy in the other positions of 204, 4853, or 16249. Therefore, we suggest that it is required of combinatory analysis on several key nucleotide positions to obtain good results when determining mitochondrial haplogroups.

Even though mitochondrial DNA analysis is performed in the field of molecular genetics, differences of the results exist regarding which nucleotide positions are analyzed. In this study, we strategically analyzed to find ethnic specific SNP of coding regions of mitochondrial DNA of Korean and Mongolian. Mitochondrial DNA was analyzed with PCR amplification and sequencing with 112 blood samples of Korean and 92 blood samples of Mongolian. As a result, the mutation which commonly appears both in Korean and Mongolian population is 17 nucleotide positions, and the one that shown in the only Korean is 13 nucleotide positions, the one that shown in the only Mongolian 26 nucleotide positions. However, it was thought as individual variation as most mutations are shown in a sample. Among them, it appears as 9% substitution rate in 10397, 4850 nucleotide position of Korean, whereas 12.3% or 15% substitution rate in 5108, 9950 nucleotide positions of Mongolian, respectively. Beside, we observed high level of heteroplasmy in 3546, 3553 nucleotide positions. Therefore, we suggest that these regions might be novel genetic markers for dividing mitochondrial haplogroup of Korean and Mongolian population, but additional analysis needs on several nucleotide positions in huge samples as analyzing on restricted nucleotide positions using restricted DNA samples.