Mitochondrial DNA (mtDNA) D-loop Polymorphism Between Koreans And Han Nationality In Yanbian, China

Objective In order to analyzing the original relationships between Korean and Han nationality, we studied the the sequence of the major noncoding (D-loop) region of human mtDNA from Korean and Han nationality in Yanbian, and the result was used to compare the relation with Chinese minority and other populations in Asian and in the world. Methods By analyzing the sequence of the major noncoding (D-loop) region of human mtDNA from Korean and Han nationality in Yanbian, the population was made up of 100 individuals (includ 50 Korean persons and 50 Han nationality persons). The sequence was observed from ntl5896 to nt 16569 and nt1 to nt100 by the PCR enlargement and sequence analyzing, and the whole sequence length was 773bp. The result was compared with the Cambridge Reference Sequence in order to analyze the genotypes. We also calculated the interpopulational (dxy), intrapopulational (dx or dy) and net nucleotide diversity (dA) between two populations in Yanbian according to genotypes, the Neighbor-Joining phylogenetic tree was built to analyze the relationship of genetic and origin among the different nationalities and populations. Futhermore, the intergenic COII/tRNA^Lys 9-bp deletion was observed in very population of two nationalities with varying frequencies, and the result was compared with others. Results We got 60 different sequence types on basis of a comparison of 773 bp sequences in 100 individuals, and the result of D-loop sequence variation suggests that all 100 individuals were mainly classified to 4 monophyletic clusters, (C1,C2,C3 and C4), and the intergenic COII/tRNA^Lys 9-bp deletion mainly was belongto Cl group. Many same or resemble mutation types were found between mainland Japanese and Korean in China, and the net nucleotide diversity (dA) was 0.033 between Korean and Han nationality. A genotype which belonged to Europe was observed in a Korean in China. The frequency of intergenic COII/tRNAlys 9-bp deletion was 12% in Korean in China, and it was lower than South Korean's 8%, and the frequency of deletion in Han nationality was 20%. According to phylogenetic tree by the Phylip computer software making, we found the closer relation between Koreans in China and mainland Japanese. Conclusion It may have the same origins between mainland Japanese and the Korean in China, and there are the shorter genetic distance (0.033) between Korean and Han nationality, but far distances among Korean in China, African original inhabitant and American Indian. Moreover, it maybe exist the European genetic factor during the origin of Korean in China, and the situation of live together for long time advanced the communion and amalgamation between Korean and Han nationality.