Jung Bin Lee

Sequence variation of mitochondrial DNA control region in Koreans

The sequencing data for two mtDNA segments in control region I and II, 385 and 341 nucleotides long, respectively, for 306 unrelated Koreans are presented. In regions I and II, 139 and 58 polymorphic sites, respectively, were noted. These were distributed evenly along the control region, though the frequency of each site was variable. Nucleotide substitution rather than insertion/deletion was the prevalent pattern of variation. A total of 265 different mtDNA lineages in region I and 154 in region II were revealed. This result represents a substantial level of polymorphism in a defined population, and presents the possibility that mtDNA polymorphism could be used as an individual identification marker, especially when nuclear DNA is not available. In view of the complex pattern of variation, meticulous test-sequencing is thought to be more appropriate than RFLP analysis using restriction endonuclease or hybridization using an SSO probe. Racial differences with genealogical usage are also described.

Polymorphism in the mitochondrial cytochrome B gene in Koreans. An additional marker for individual identification.

Sequencing the mitochondrial control region is very useful for individual identification when conventional DNA typing using autosomal STRs is unavailable. However, low discriminatory power is a problem and another polymorphic locus within the mitochondrial genome is necessary. The cytochrome B (MTCYB) gene, which has undergone several changes during evolution, may be a good candidate for this purpose. Here the sequencing data of the MTCYB gene of 98 unrelated Koreans is presented. A total of 30 polymorphic sites were found which were distributed evenly along the gene. All were nucleotide substitutions and no insertions/deletions were noted. A total of 22 different MTCYB lineages were revealed. Out of 22 different control region lineages with 79 samples which shared the same D-loop sequence with some others within a lineage, 10 lineages with 37 samples could be sub-grouped according to different MTCYB sequences. Some issues concerning the MTCYB gene polymorphism are discussed.