A proof of principal study on the use of direct PCR of semen and spermatozoa and development of a differential isolation protocol for use in cases of alleged sexual assault.

Sexual assault samples are some of the most common samples encountered in forensic analysis. These samples can require a significant time investment due to differential extraction processes. We report on the first record of successful direct amplification of semen for STR analysis.

A comparison between direct PCR and extraction to generate DNA profiles from samples retrieved from various substrates.

Direct PCR generates DNA profiles from samples without using the extraction process. During sample extraction, DNA may be lost due to the methods used, which can affect the quality of the DNA profile obtained. This is not the case with direct PCR, where the sample is transferred directly into the PCR tube.

Generation of DNA profiles from fabrics without DNA extraction.

DNA profiles can be obtained from fabrics where a person has made direct contact with clothing. A standard approach is to cut out a section of the fabric and then use a commercially available method to extract and isolate the DNA. Alternative methods to isolate DNA include the use of adhesive tape to remove traces of cellular material from the fabric prior to extraction.

Haplotype diversity of 17 Y-chromosomal STRs in three native Sarawak populations (Iban, Bidayuh and Melanau) in East Malaysia.

17 Y-STRs (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a/b, DYS393, DYS391, DYS439, DYS635 or Y-GATA C4, DYS392, Y-GATA H4, DYS437, DYS438 and DYS448) have been analyzed in 320 male individuals from Sarawak, an eastern state of Malaysia on the Borneo island using the AmpFlSTR Y-filer (Applied Biosystems, Foster City, CA). These individuals were from three indigenous ethnic groups in Sarawak comprising of 103 Ibans, 113 Bidayuhs and 104 Melanaus. The observed 17-loci haplotypes and the individual allele frequencies for each locus were estimated, whilst the locus diversity, haplotype diversity and discrimination capacity were calculated in the three groups.