Differential distribution of human mitochondrial DNA in somatic tissues and hairs.
To investigate mitochondrial DNA (mtDNA) distribution within tissues during life, we observed length heteroplasmy in a polycytosine tract of the mitochondrial HV2 region by size-based separation of PCR products, using a mutagenic primer which was designed to avoid stutter production. Blood, brain, heart, liver, skeletal muscle and hair shaft samples were collected during autopsies of 25 individuals. Here, we demonstrate differences in the level of mtDNA length heteroplasmy both within and between individuals and tissues. We also show that mtDNA is distributed randomly in varying proportions in various somatic tissues during growth, resulting in an imbalance in the composition of mtDNA pools among tissues. This mtDNA distribution appears not to be strictly random, and can be explained by the random somatic segregation of nucleoids. On the other hand, significant qualitative/quantitative mtDNA peak pattern variations in hair shafts are thought to be a result of the different developmental origins of hairs. Each hair shaft may have a restricted or clonal set of mtDNA molecules derived from a discrete group of stem cells.
Lee
Hwan Young
HY
Department of Forensic Medicine and Brain Korea 21 Project for Medical Science, College of Medicine, Yonsei University, 134 Shinchon-Dong, Seodaemun-Gu, Seoul 120-752, Korea.
Chung
Ukhee
U
Park
Myung Jin
MJ
Yoo
Ji-Eun
JE
Han
Gil-Ro
GR
Shin
Kyoung-Jin
KJ
D000367:Age Factors; D001483:Base Sequence / Q000235:genetics*; D001923:Brain Chemistry; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000097:blood / Q000235:genetics*; D019075:Electrophoresis, Capillary; D014644:Genetic Variation; D005838:Genotype; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008099:Liver / Q000737:chemistry; D018482:Muscle, Skeletal / Q000737:chemistry; D009206:Myocardium / Q000737:chemistry; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D004272:DNA, Mitochondrial