Interpretation of C tract in the D-Loop of Mitochondrial DNA.

Kim, Ji Young; Kim, Jin Hee; Shen, Yu Lan; Lee, Won Joon; Lee, Ho; Park, Jong Tae

Original article

Korean Journal of Legal Medicine 2002;26(2):42-50.
Published online October 31, 2002.

Interpretation of C tract in the D-Loop of Mitochondrial DNA.

Ji Young Kim, Jin Hee Kim, Yu Lan Shen, Won Joon Lee, Ho Lee, Jong Tae Park

¹Department of Forensic Medicine, Chonnam National University Medical School, Korea.
²National Institute of Scientific Investigation, Western District Office, Korea.

Abstract

The D-loop of mitochondrial DNA contain C tracts(homopoymeric cytosines) in the positions of 16183 -16193, 303 -315, 568 -573 of GI 1944628 of NCBI. When the sequence of these positions are analyzed, the sequencing reactions or their signals after the C tract were abruptly decreased and cannot clarify the nucleotide signals in many cases. It is hard to characterize of the C tract. To characterize the C tract, we tried to analyze the sequence of clone and amp-length polymorphism with silver stain after amplification of small fragments including C tract of 16183 -16193 and 303-315.These results were compared with the results of characterization of nucleotides after separation of each nucleotide signal from the electropherogram which were increased in the Y axis to intensify the small overlapped signals using CHROMAS program. All methods we tried showed similar pattern of heteroplasmies of homopolymeric cytosines. Conclusively, it is not necessary to try resequencing reaction after cloning or amp-length polymorphism using silver stain. Intensification of the small overlapped signals in Y axis and separation of each signal is enough method to characterize the C tract.

Key Words: Mitochondrial DNA, C tract, Heteroplasmy