Study Of MtDNA Sequence Diversity And Its Application In Forensic Science

Objective The D-loop region of the Mitochondrial DNA provides a very useful tool for forensic science studies. It is true in difficult cases, such as degraded DNA or samples containing minimal amounts of genomic DNA. To investigate the sequence diversity of mtDNA in Taiyuan Han population, mtDNA nt16081-16546 sequences were determined in 58 unrelated Han Chinese from Taiyuan. SSCP method was developed as one of screening measures which were used to examine polymorphism of mtDNA, so as to supply a rapid and simple method for forensic casework.Method DNA of 58 unrelated individuals was supplied by No.l hospital of Shanxi Medical University and extracted by phenol-chloroform method. After PCR, the sequencing fragments were generated and analysed using dRhodamine Terminator Cycle Sequencing Ready Reaction Kit and ABI 377 respectively. MtDNA of hairs, bones, nails were sequenced. Different tissues of one corpse were analysed including hairs, muscle, heart, liver, ets. 20 mother-offspring pairs wereinvestigated to detect mutations of mtDNA. The amplified products were also analysed using single-strand conformation polymorphism (SSCP) on 10% non-denaturing PAG containing 10% glycerol.Result and conclusion In our Han database, 55 different haplotypes were obtained in 58 individuals, and 53 haplotypes occurred in single individuals, and two haplotypes were shared by two and three ones respectively. GD was 99.76%. There are 74 variations in nt16081-16546. Sequence diversity were caused by nucleotide substitution. The mean pairwise difference calculated for ntl 6081-16546 was 4.586. The genetic data from our population was similar to those calculated for other three Han populations that came from Beijing, Liaoning and Taiwan and different distinctively from South West Swiss population. It was found that the sequences of mtDNA nt 16081-16546 region of different hairs from the same individual were different. He was heteroplasmic. There was difference in mtDNA sequence between one mother-offspring pair, the sequence of the mother contained 16193. 2c while the child was 16193. c. It was caused by heteroplasmy or mutations. The discrimination rate of SSCP was 62.5% .SSCP supplied a rapid and straightforward screening of mtDNA variations and can be implemented for forensic cases.