Search

Population allele frequency is an indicator of population genetic diversity and plays significant roles in DNA profiling interpretation in human identification, kinship, and forensic testing. The Lebanese population is a mosaic of 18 religious communities with high rates of consanguinity and endogamy. Allele frequencies for 23 STR loci were estimated and analyzed in the seven major Lebanese religious subcommunities (Muslims Shiaa, Sunni, and Druze, and Christians Orthodox, Maronite, and Catholics), to assess possible significant differences among their STR allele frequencies. [ABSTRACT FROM AUTHOR]

Disaster victim identification (DVI) often occurs in remote locations with extremes of temperatures and humidities. Access to mortuary facilities and refrigeration are not always available. An effective and robust DNA sampling and preservation procedure would increase the probability of successful DNA profiling and allow faster repatriation of bodies and body parts. If the act of tissue preservation also released DNA into solution, ready for polymerase chain reaction (PCR), the DVI process could be further streamlined. In this study, we explored the possibility of obtaining DNA profiles without DNA extraction, by adding aliquots of preservative solutions surrounding fresh human muscle and decomposing human muscle and skin tissue samples directly to PCR. The preservatives consisted of two custom preparations and two proprietary solutions. The custom preparations were a salt-saturated solution of dimethyl sulfoxide (DMSO) with ethylenediaminetetraacetic (EDTA) and TENT buffer (Tris, EDTA, NaCl, Tween 20). The proprietary preservatives were DNAgard (Biomatrica) and Tissue Stabilising Kit (DNA Genotek). We obtained full PowerPlex 21 (Promega) and GlobalFiler (Life Technologies) DNA profiles from fresh and decomposed tissue preserved at 35 °C for up to 28 days for all four preservatives. The preservative aliquots removed from the fresh muscle tissue samples had been stored at −80 °C for 4 years, indicating that long-term archival does not diminish the probability of successful DNA typing. Rather, storage at −80 °C seems to reduce PCR inhibition. [ABSTRACT FROM AUTHOR]

When DNA evidence is used to implicate a suspect, it may be of interest to know whether it is likely that the suspect's near relatives also share the suspect's DNA profile. In this study we discuss methods for evaluating the probability that at least one of a set of the suspect's full or half-siblings shares the suspect's DNA profile. We present three such methods: exact calculation, estimation via Monte Carlo simulations, and estimation by means of sandwiching the probability between an upper and a lower bound. We show that, under many circumstances, this upper bound itself provides an extremely quick and accurate estimate of the probability that at least one of the relatives matches the suspect's profile. [ABSTRACT FROM AUTHOR]

This study describes the validation of short tandem repeat (STR) systems for the resolution of cases of disputed parentage where only a single parent is available for testing or where the claimed relationship of both parents is in doubt and also cases where sibship must be tested. Three separate multiplex systems the Second Generation Multiplex, Powerplex 1.2 and FFFL have been employed, giving a total of 16 STR loci. Both empirical and theoretical approaches to the validation have been adopted. Appropriate equations have been derived to calculate likelihood ratios for different relationships, incorporating a correction for subpopulation effects. An FST point estimate of 1% has been applied throughout. Empirically, 101 cases of alleged father, alleged mother and child where analysed using six SLP systems and also using the three multiplex STR systems. Of the 202 relationships tested, 197 were independently resolved by both systems, providing either clear evidence of non-parentage or strong support for the relationship. [ABSTRACT FROM AUTHOR]

If the DNA profiles of a crime stain and the reference sample from the suspect do not match, the suspect is excluded as the donor of the crime stain. However, in some situations the DNA evidence can suggest that a close relative of the suspect might match the stain, in particular when the reference sample from the suspect and the crime stain share rare alleles. This finding can be important for the authorities. The forensic scientist has to decide whether or not to notify the authorities in these circumstances. To the best of our knowledge there is not yet an objective rule for making this decision. We propose such a decision rule for brothers of the suspect, investigate its performance and address some ethical, legal, and practical aspects. Our calculations can be simply adjusted for other relatives of the suspect. [ABSTRACT FROM AUTHOR]