Forensic identification by DNA fingerprinting and mitochondrial DNA typing.

Short tandem repeats (STRs), that represent an important source of highly polymorphic markers in human genome, and mitochondrial DNA (mtDNA) typing, that its sequences were conserved within the same maternal lineage, facilitated by use of the polymerase chain reaction (PCR) provide a powerful tool for forensic identification. We report the analysis of 9 STR loci and mtDNA typing of a muscle biopsied sample with 2 months postmortem by comparison with the genotype of the relative. The DNA profile showed common alleles with that of the relative but only 12 from 20 alleles (60%) were identifiable. Then, we performed mt DNA sequencing of the hypervariable region I (HV I) and obtained 100 per cent homology with that of the relative. In conclusion, personal identification can be performed precisely by the data of DNA profile and mtDNA typing compared to the genotype of the relative.

Paternity testing by PCR-based STR analysis.

We present application of polymerase chain reaction (PCR)-based short tandem repeat (STR) system for use in paternity testing. The process involves a single tube multiplex PCR of 9 STR loci on different chromosomes, in conjunction with Amelogenin sex test and internal size standards, followed by using an automated DNA sequencer to detect amplified products. The results showed that this system provided unambiguously reliable results. In addition, the method is useful for routine use in that it is robust and reproducible and provides a reliable means of paternity testing.

BCR/ABL rearrangement in Philadelphia chromosome negative CML patients.

Reverse transcription-polymerase chain reaction (RT-PCR) was used to study 34 patients with chronic myelogenous leukemia (CML) associated with negative Philadelphia (Ph) chromosome. This report showed evidence of a chimeric BCR/ABL transcript in 18 (52.9%) and 28 (82.4%) cases by first PCR and seminested PCR, respectively. In these BCR/ABL transcript positive cases, the incidence of BCR exon3/ABL exon2 (B3A2) and BCR exon 2/ABL exon2 rearrangement was 25 (89.3%) and 3 (10.7%) cases, respectively. The other 6 Ph negative patients showed no evidence of reciprocal translocation of BCR to chromosome 9. This data demonstrates that seminested PCR is sufficiently sensitive to detect BCR/ABL fusion transcript in Ph chromosome negative CML patients.

Comparison of DNA extraction from blood stain and decomposed muscle in STR polymorphism analysis.

Forensic samples that are often degraded and limited in quality cause DNA typing analysis by conventional methods unsuitable. We performed a single tube-multiplex PCR on 9 STR loci (D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820) and the X-Y homologous gene amelogenin of DNA extracted from six week postmortem blood stain and decomposed muscle by using QIAGEN QIAamp blood or tissue procedure. An automated genetic analyzer based on fluorescent dye technology was used to detect STR allele patterns. The DNA profile of blood stain sample obtained a complete and unambiguous pattern, whereas, that of muscle DNA extracted from QIAamp tissue and Chelex plus QIAamp blood protocols showed detected STR alleles for 70 per cent and 50 per cent of all tested alleles, respectively. The degraded muscle DNA could not yield amplified products of large size STR alleles; CSF1PO, D13S317 and D7S820. However, the analysis which relied upon the PCR-based STR polymorphism analysis and automated genetic analyzer system offers an ideal strategy for forensic identification.