DNA

Mouth swab samples taken under the Police and Criminal Evidence Act (PACE) are tested in our dedicated PACE laboratory providing rapid, cost-effective and high-throughput analysis of reference samples. DNA17 profile results are loaded to the National DNA Database or made available to Reporting Officers for comparison.

The use of a single sample type allows for a high degree of automation and streamlining of this process. We have optimised the NDNAD-approved ESI17 FAST chemistry to enable highly efficient processing with large batch sizes of up to 384 samples analysed in a single test plate. This increases the processing capacity and enables rapid reporting of samples in as little as X (insert any relevant KPIs as required). 

Other reference samples, such as volunteer samples; elimination samples from police staff or our own forensic teams; other sample types such as hairs, tissue or pathology samples; and reference samples for Y-STR uses are also processed through this laboratory.

Our DNA Crime Stain team carries out DNA profiling from a wide range of sample types including body fluid stains, hairs, cigarette ends and non-visible traces of cellular DNA. Sweat and skin flakes recovered from the inside of garments and footwear can yield DNA profiles where the identity of the wearer may be in doubt.  Handled tools, weapons or any other item that may have been touched during the course of an incident could also be relevant to an investigation. 

Many of our received samples have only trace amounts of DNA present. It is key to successful DNA profiling to be able to recover and purify the maximum amount of DNA possible from such items. Our laboratory processes are specifically optimised to maximise the DNA yields from small amounts of biological material and to deliver highly purified DNA samples to give the best possible chance of successful DNA profiling.

In common with forensic laboratories around the world, our method of choice for nearly all DNA analyses is autosomal DNA testing using an approved DNA17 STR chemistry, in our case the ESI17 FAST system. However, we also have available an number of alternative analytical methods, including autosomal STR DNA24 systems for use when specific circumstances require them.

Results from crime stain profiling are either loaded directly to the NDNAD to search for matching individuals or other crime sample profiles, or are returned to our casework reporting officers for comparison to suspects or other profiles of interest in the case.

In addition to our standard DNA17 profiling line, we have developed and continue to expand a set of specialist DNA techniques which, used together, give our scientists the best chance of discovering information from samples of DNA, however small, mixed or degraded. They include:

• DART (Direct Ammunition Recovery Technique): A bespoke technique developed at Eurofins for the recovery of DNA from both fired and unfired cartridges up to and including 9mm calibre. DART is also suitable for use on certain other non-porous items.
• Bones and teeth: A simplified and streamlined approach to the preparation of bone and teeth for DNA extraction, and the integration of the subsequent DNA recovery and purification steps into our routine processing line provides improved quality of results and increased capacity for this sample type.
• Y-STRs for analysis of male DNA: This is especially useful in mixed male/female samples, common in sexual offence cases, where a very small amount of male DNA may be present in a large background of female DNA from the victim.
• Familial searching of the National DNA Database: Our Familial Search software, developed by our forensic statisticians at Eurofins, allows us to work with the NDNAD to search for potential relatives of an unidentified perpetrator, with results ranked in order of interest.