The Genotyping by the Nucleotide, Length, and Quantitative Polymorphism of C-stretch of HVR I of mtDNA D-Loop / 대한법의학회지

To analyze the nucleotide polymorphism and length polymorphism of C-stretch of HVR 1 (Hypervariable Region I) of mtDNA D-loop in the maternal lineages in Koreans, sequencing of C-stretch, GeneScan analysis and cloning of a cases were performed in 266 random objects and 128 families which were confirmed by STR analysis of autosome, X chromosome and nucleotide polymorphism of mitochondrial DNA D-loop. C- stretch was classified into two groups. First group (the group of nucleotide polymorphism 74.2%) has 14 bases which show nucleotide polymorphism composed of adenine, cytosine and thymine without length polymorphism and second group (poly C tract 25.8%) shows length polymorphism by the changes of the number of adenine and cytosine. The patterns of nucleotide polymorphism were as follows: A4C5TC4 (64.8%), A4C5TC2TC (0.8%), A4C4TTC2TC (0.8%), A4C3TCTC4 (5.5%), A4C2TC2TC4 (0.8%), A4CTC3TC4 (0.8%), A4TC4TC4 (0.8%). The pattern of length polymorphism of poly C tract were as follows : LP10-16 (3.0%), LP11-16 (6.1%), LP11-17 (27.2%), LP11-18 (6.1%), LP12-16 (12.1%), LP12- 17 (39.4%), LP12-18 (3.0%), LP13-16 (3.0%) The copy number ratios of each fragment length in the same pattern of length polymorphism were various, and this data were valuable in individual identification because of the quantitative polymorphism of each fragment length. The correlation coefficients of copy number ratio of each fragment length in the families were more than 0.98 in 84.8% (28 of 33 families) of cases, which was interpreted as maternal inheritance of the copy number ratio of fragment length. However, in some cases (9.1%, 3 of 33 families), the correlation value of fragment length were less than 0.96 and in 2 cases of 33 families (6.1%), were 0.89 and 0.75 which suggested a possibility of mutation in the quantitative polymorphism although the length polymorphism were maternally inherited. From the above results, sequencing analysis of nucleotide polymorphism and GeneScan analysis of C- stretch must be combined to clearly identify the nucleotide polymorphism, length polymorphism, and quantitative polymorphism of C-stretch of HVR 1 of mtDNA D-loop.

Polymorphism and Mutation of C-Stretch of the D-loop of Mitochondrial DNA / 대한법의학회지

To investigate the polymorphism and mutation of the C-stretch of the D-loop in mitochondrial DNA in the maternal lineages in Koreans, Amp-FLP (amplified fragment length polymorphism), cloning and sequencing, and analysis of overlapped signals of the end of C-stretch after enlargement of Y axis of electropherogram were performed in 104 random objects and 63 families which are confirmed by STR analysis of autosome, Y chromosome, X chromosome and D-loop of mitochondrial DNA. Analysis of Amp-FLP and enlargement of Y axis of electropherogram are better than sequencing after cloning in the analysis of C-stretch. C- stretch 16183 has 15 genotypes, C-stretch 303 has 14 genotypes, C-stretch 568 has 6 genotypes, These results are useful for individual identification. However, mutation of C-stretch 16183, C-stretch 303, and C-stretch 568 were observed in 5 (7.9%), 7 (11.1%), and 1 (1.6%) cases among the 63 families. It means the C-stretch cannot be applied to analyze the genetic pattern in the maternal lineages. Conclusively, Amp-FLP and enelargement of Y axis of electropherogram are enough for analysis of C-stretch. Analysis of C-stretch is useful for individual identification and not in the study of maternal lineages.