ABSTRACT
OBJECTIVE@#To explore the distribution and genetic pattern of heteroplasmy of mtDNA control region among Chinese Han population.@*METHODS@#The human mtDNA control region was amplified into 6 amplicons overlapped partially each other. Then these amplicons were analyzed by DHPLC which we developed to detect low heteroplasmic signals.@*RESULTS@#There were 51 heteroplasmic cases (34%) found from different tissues of 150 unrelated individuals of the Chinese Han population. mtDNA heteroplasmy shows non-uniform distribution in various tissues. The highest occurrence of heteroplasmy was in brain tissues (50/150) and myocardium (48/150), the lowest was in bone tissues (22/150). 36 sites of heteroplasmy were identified in our samples. Three sites of mtDNA heteroplasmy rarely co-existed in one individual. No sex differences were detected in the frequency of mtDNA heteroplasmy. No change in the mtDNA heteroplasmy profile was detected of blood samples from the same individuals within 2 years. Individuals older than 41 years showed a heteroplasmy frequency significantly higher than their younger counterparts. Members from the same maternal pedigree in a family can share the same sites of mtDNA heteroplasmy but may have different heteroplasmy contents at those sites.@*CONCLUSION@#DHPLC is a highly sensitive technique in detecting heteroplasmy. mtDNA heteroplasmy widely exists in the Chinese Han population. The results shown here could potentially have a guidable value in forensic individual identification and parentage testing.
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Humans , Middle Aged , Young Adult , Asian People/genetics , Base Sequence , Blood Stains , China/ethnology , Chromatography, High Pressure Liquid/methods , DNA Mutational Analysis/methods , DNA, Mitochondrial/genetics , Genetic Heterogeneity , Hair/chemistry , Mutation , Polymorphism, Genetic/geneticsABSTRACT
<p><b>OBJECTIVE</b>To explore the mutations of 15 short tandem repeat (STR) loci in PlowerPlex16 System which are world-widely used in parentage testing.</p><p><b>METHODS</b>Mutations of 15 STR loci in PlowerPlex16 System were investigated in 1921 parentage testing cases from Chinese population.</p><p><b>RESULTS</b>In 1921 parentage cases, seventy cases (3.644%) were found to have mutations. Among these were one case with double mutations (D21S11 and PentaD) and another case with two different mutations (D7S820 and D16S539) in two children. The total number of mutated STR loci observed was 72 over 3764 meiosis with a mutation rate of 0.128% +/- 0.1104% x 10(-3). The highest mutation rate was 0.292% at vWA and D21S11. No mutation was observed at TH01 or at TPOX. The mutated alleles coming from father were five times more than those from mother. The majority (98.611%) of mutated alleles were the results of one-step mutation. The ratio of one-step gain versus loss was 1.826:1. There was only one multiple-step mutation with a double-repeat gain observed at PentaD locus. In the PlowerPlex16 System, nine loci, namely D8S1179, Penta D, D13S317, D16S539, D7S820, D5S818, D3S1358, TH01 and TPOX, have lower mutation rates and are more suitable for parentage testing.</p><p><b>CONCLUSION</b>Mutation of STR is relatively common and often makes parentage testing more complicated. Selecting stable STR locus with low mutation rate is more important in parentage testing.</p>