Repeatedly washed semen stains: Optimal screening and sampling strategies for DNA analysis.

In many sexual assault cases, bedding and clothing are essential pieces of evidence that are screened for semen stains to gather DNA from the assailant. In some cases, these items have been washed before being seized and sent to the forensic lab. However, few data exist on the optimal methods for detecting and sampling semen stains on washed fabrics. In this paper, we used semen stains washed up to six times to evaluate the efficiency of commonly used screening methods for the detection of semen: alternate light source (ALS), acid phosphatase (AP), prostate specific antigen (PSA) and microscopy (sperm Hy-Liter™, SHL). We also assessed different washing conditions (detergents, washing machines, addition of bleach) and sampling methods (cutting and swabbing). The results show that some semen stain detection strategies, such as ALS, PSA, and SHL, are effective even when the item was washed multiple times. We also show that a complete genetic profile could be obtained from semen stains washed six times. Based on these findings, we present different strategies for the detection and sampling of semen stains depending on the circumstances of the case.

DNA transfer during laundering may yield complete genetic profiles.

In a number of child sexual abuse cases, the alleged perpetrator is a member of the nuclear family. In those cases, there is a possibility that the suspect's DNA was innocently deposited onto the child's clothing without acts of sexual assault ever occurring, for example via secondary transfer within the washing machine. To assess the quantity and quality of DNA that may be transferred among clothing during laundering, we conducted three series of experiments. First, we evaluated the level of spermatozoa that may be transferred by washing pristine pairs of underwear with bed sheets containing a varying number of ejaculates. Secondly, we explored whether current genetic methods may also detect the transfer of DNA from vaginal secretions during a machine wash. Finally, we analyzed the background levels of DNA on children's underwear collected from control families where sexual abuse never occurred. For both spermatozoa and vaginal secretions, we revealed that sufficient amounts of DNA may transfer onto laundered clothing to yield complete genetic profiles. Furthermore, DNA from relatives living within the same household was found in most cuttings taken from control children's underwear. Based on these findings, we present a framework for the handling and interpretation of intrafamilial sexual abuse cases. These suggestions should help determine whether DNA was deposited directly onto a fabric or merely transferred during a wash.

Leading-edge forensic DNA analyses and the necessity of including crime scene investigators, police officers and technicians in a DNA elimination database.

In recent years, sophisticated technology has significantly increased the sensitivity and analytical power of genetic analyses so that very little starting material may now produce viable genetic profiles. This sensitivity however, has also increased the risk of detecting unknown genetic profiles assumed to be that of the perpetrator, yet originate from extraneous sources such as from crime scene workers. These contaminants may mislead investigations, keeping criminal cases active and unresolved for long spans of time. Voluntary submission of DNA samples from crime scene workers is fairly low, therefore we have created a promotional method for our staff elimination database that has resulted in a significant increase in voluntary samples since 2011. Our database enforces privacy safeguards and allows for optional anonymity to all staff members. We also offer information sessions at various police precincts to advise crime scene workers of the importance and success of our staff elimination database. This study, a pioneer in its field, has obtained 327 voluntary submissions from crime scene workers to date, of which 46 individual profiles (14%) have been matched to 58 criminal cases. By implementing our methods and respect for individual privacy, forensic laboratories everywhere may see similar growth and success in explaining unidentified genetic profiles in stagnate criminal cases.

Suggestive evidence for a new locus for epilepsy with heterogeneous phenotypes on chromosome 17q.

PURPOSE: To characterize the clinical features and molecular genetic background in a family with various epilepsy phenotypes including febrile seizures, childhood absence epilepsy, and possible temporal lobe epilepsy. METHODS: Clinical data were collected. DNA and RNA were extracted from peripheral blood. A genome-wide microsatellite marker scan was performed and regions with a multipoint location score > or =1.5 were fine mapped. Functional candidate genes identified from databases and by comparing gene expression profiles of genes between affected and unaffected individuals were sequenced. Copy number variation was evaluated with array-based comparative genomic hybridization. RESULTS: The seizure phenotype was benign. Inheritance was consistent with an autosomal dominant model and reduced penetrance. The highest two-point LOD score of 2.8 was identified at marker D17S1606 in a 37cM interval on chromosome 17q12-q24. Loci on 5q11.2 and on 18p11-q11, showed LOD scores > or =1.5 after fine mapping. Sequencing of nine ion-channel genes and two (RPIP8 and SLC25A39) differentially expressed genes from 17q12-q24, as well as IMPA2 from 18p11-q11 did not reveal a pathogenic alteration. No clinically relevant copy number variation was identified. CONCLUSIONS: Our findings suggest complex inheritance of seizure susceptibility in the family with contribution from three loci, including a possible new locus on chromosome 17q. The underlying molecular defects remain unknown.