Swiss Caucasian population data for the STR loci D2S1338 and D19S433 using the AmpFISTR SGM plus PCR amplification kit

Use of DNA profiles for investigation using a simulated national DNA database: Part I. Partial SGM Plus profiles

In traditional criminal investigation, uncertainties are often dealt with using a combination of common sense, practical considerations and experience, but rarely with tailored statistical models. For example, in some countries, in order to search for a given profile in the national DNA database, it must have allelic information for six or more of the ten SGM Plus loci for a simple trace. If the profile does not have this amount of information then it cannot be searched in the national DNA database (NDNAD). This requirement (of a result at six or more loci) is not based on a statistical approach, but rather on the feeling that six or more would be sufficient. A statistical approach, however, could be more rigorous and objective and would take into consideration factors such as the probability of adventitious matches relative to the actual database size and/or investigator's requirements in a sensible way. Therefore, this research was undertaken to establish scientific foundations pertaining to the use of partial SGM Plus loci profiles (or similar) for investigation.

Quantification of chimerism within peripheral blood, bone marrow and purified leukocyte subsets: comparison of singleplex and multiplex PCR amplification of short tandem repeat (STR) loci

OBJECTIVE AND METHODS

Chimerism analysis has become a routine diagnostic procedure after haematopoietic allogeneic stem cell transplantation for early detection of relapse of disease or graft failure. Whereas some centres developed individual in-house short tandem repeat (STR) systems, others prefer commercial multiplex PCR systems. However, little is known about inter-assay variation, which could have a significant impact on treatment decision. We therefore compared two commercial multiplex PCR kits with our in-house STR system using different sample sources, such as peripheral blood (PB), bone marrow (BM) and specific leukocyte subsets.

RESULTS

Fifty samples of eighteen paediatric patients were analysed. For neither material, PB, BM and leukocyte subtypes, a significant difference between the STR systems tested was observed. Chimerism analyses of each single STR primer, which is component of both the in-house and the commercial STR system, did not reveal significant differences.

CONCLUSION

Our analysis demonstrates that similar results can be obtained with both assays, even when using various sample sources. Further evaluation of different test systems will help to increase interlaboratory standardisation of chimerism analyses for early clinical intervention.

Forensic identification of urine samples: a comparison between nuclear and mitochondrial DNA markers

Urine samples from 20 male volunteers of European Caucasian origin were stored at 4 degrees C over a 4-month period in order to compare the identification potential of nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) markers. The amount of nDNA recovered from urines dramatically declined over time. Consequently, nDNA likelihood ratios (LRs) greater than 1,000 were obtained for 100, 70 and 55% of the urines analysed after 6, 60 and 120 days, respectively. For the mtDNA, HVI and HVII sequences were obtained for all samples tested, whatever the period considered. Nevertheless, the highest mtDNA LR of 435 was relatively low compared to its nDNA equivalent. Indeed, LRs obtained with only three nDNA loci could easily exceed this value and are quite easier to obtain. Overall, the joint use of nDNA and mtDNA markers enabled the 20 urine samples to be identified, even after the 4-month period.

STR data for the AmpFlSTR SGM Plus loci from Shantou (south of China)

Allele frequencies for the ten STRs included in the AmpFlSTR SGM Plus kit were obtained from a sample of 132 unrelated Han individuals born in the region of Shantou (south of China).