![]() Other characteristic features of the mtDNA are the intronless genes and the limited, or even absent, intergenic sequences, except in one regulatory region. All the 13 protein products are part of the enzyme complexes that constitute the oxidative phosphorylation system. The heavy (H) strand encodes more information, with genes for two rRNAs (12S and 16S), twelve polypeptides and fourteen tRNAs, while the light (L) strand encodes eight tRNAs and one polypeptide. mtDNA strands have different densities due to different G+T base composition. ![]() However, the complete sequence of the first mtDNA was only published and established as the mtDNA Cambridge Reference Sequence (CRS) eighteen years later, in 1981 ( Anderson et al., 1981).Įssentially, the mtDNA is a five mm histone-free circular double-stranded DNA molecule, with around 16 569 base-pairs and weighting 10 7 Daltons ( Taanman, 1999). The mitochondrial DNA (mtDNA) was first identified and isolated by Margit Nass and Sylvan Nass in 1963, who studied some mitochondrial fibers that according to their fixation, stabilization and staining behavior, appeared to be DNA related ( Nass & Nass, 1963). Mitochondria are cellular organelles that contain an extrachromosomal genome, which is both different and separate from the nuclear genome. Nevertheless, and despite the robustness of mtDNA in cases of exclusion or absence of identity between sequences, when the results are sequence identity, contrary to nuclear markers, they do not refer to an individual but to a group of individuals of the same maternal lineage. In these cases the study of mitochondrial DNA (mtDNA) for human identification can be the last appeal and by that reason has become routine ( Budowle et al., 2003). However, in a considerable number of situations of human identification, autosomal DNA is highly degraded or isn’t available at all. In accordance with international recommendations, particularly with recommendations of the European DNA Profiling Group (EDNAP), currently, only genetic profiles obtained from autosomal short tandem repeats (STR) should be used for genetic fingerprinting. A genetic profile or the genetic fingerprint of an individual is the phenotypic description of a set of genomic loci that are specific to that individual. CONCLUSIONS Whole mtDNA sequencing distinguished between individuals from 47 Chongqing Han populations in southwest China and has potential applications that include high-quality forensic identification.Human genetic identification for forensic purposes is achieved through the definition of genetic profiles. The subpopulation effects showed 20 times the differences in match probability when compared with south China regions. Expanding the sequencing rage increased the discrimination power of mtDNA from three-times to 25-times based on different populations. RESULTS The whole mtDNA sequencing data of 47 southwest Chinese Han populations were successfully recovered. Analysis of molecular variance (AMOVA) was performed, and 1257 hypervariable region data sets were added to the principal component analysis (PCA). Pairwise fixation index (FST), a measure of population differentiation due to genetic structure, were calculated. The extent of the effects of the mtDNA on the subpopulations was investigated and compared with six other populations from published studies. ![]() MATERIAL AND METHODS The mtDNA of 47 Chongqing Han populations was generated using the Ion Torrent Personal Genome Machine (PGM) system. This study aimed to use whole mtDNA sequencing to investigate 47 Chongqing Han populations in southwest China and the diversity in the mtGenome reference data. Due to the rapid development of sequencing technology, whole mtDNA sequencing is now possible and may be used in epidemiological and forensic studies. BACKGROUND Mitochondrial DNA (mtDNA) sequencing has been used in many areas, including forensic genetics.
0 Comments
Leave a Reply. |