Genotyping DNA isolated from UV irradiated human bloodstains using whole genome amplification

Molecular Biology Reports - Analysis of DNA polymorphisms are the primary technique used for personal identification in forensic cases. However, DNA samples collected as evidence from crime scenes...     

Genetic analysis of twelve X-chromosomal STRs in Japanese and Chinese populations

We investigated the genetic markers of twelve X-STR loci in 670 healthy, unrelated Japanese (438 men and 232 women) from Tokyo and 488 Chinese (263 men and 225 women) from Shenyang, using the Investigator Argus X-12 kit. Allele and haplotype analyses of twelve X-STRs clustered into four linkage groups indicated that they are highly informative for forensic applications in Japanese and Chinese populations. Hardy–Weinberg equilibrium tests demonstrated no significant deviations in the two populations. Among the four closely linked X-STR trios, some haplotype unique to Japanese or Chinese population were detected. Haplotype diversity for each linkage group ranged from 0.9861 to 0.9968, showing high values in each of the study populations. The genetic distances between populations based on the 12 X-STR loci and the phylogenetic tree revealed long genetic distances between Asian and Caucasian populations and between Asian and African population (Moroccan). These results suggest that the twelve X-STR loci will contribute to forensic casework in Japanese and Chinese populations.     

DNA repair and STR PCR amplification from damaged DNA of human bloodstains

Detection and identification of DNA structure from aged and damaged biological materials such as bloodstain are important for human genetic study and individual identification. However, after a long period of storage, the DNA structure of biological samples is degraded to various degrees depending on several factors including environmental condition. In this study, human bloodstains that have been stored at room temperature for one to 39 years were used to represent damaged biological samples. The numbers of apurinic/apyrimidinic sites (AP sites) were investigated by the DNA Damage Quantification Kit to evaluate the lesions in DNA structure. The damaged DNA from the stored human bloodstains was repaired using seven DNA repair enzymes. As DNA genetic marker, short tandem repeat (STR) genotypes were amplified using the non-repaired and repaired DNA preparations from the stored bloodstains. The results indicated that the number of AP sites increased as the storage time increased. While only 2 to 6 STR loci were detected in the damaged DNA of bloodstains stored for over 30 years, after DNA repair all the genotypes in the STR system could be analyzed even from bloodstains that had been stored for the longest period.