Scientists develop faster, more cost-effective DNA test for crime scenes

Scientists in Japan are reporting development of a faster, less expensive version of the fabled polymerase chain reaction (PCR), which is a DNA test widely used in criminal investigations, disease diagnosis, biological research and other applications.

According to the researchers, the new method could lead to expanded use of PCR in medicine, the criminal justice system and elsewhere.

In the new study, scientist Naohiro Noda and his team note that PCR works by "amplifying" previously undetectable traces of DNA almost like photocopiers produce multiple copies of documents.

With PCR, crime scene investigators can change traces of DNA into amounts that can be identified and linked to a suspect.

Biologists can produce multiple copies of individual genes to study gene function, evolution, and other topics.

Doctors can amplify the DNA from microbes in a patient's blood to diagnose an infection.

Current PCR methods, however, are too expensive and cumbersome for wide use.

The scientists describe development and testing of a new PCR method, called the universal QProbe system, which overcomes these problems.

Existing PCR processes require several "fluorescent probes" to seek out DNA.

QProbe substitutes a single "fluorescent probe" that can detect virtually any target, saving time and cutting costs.

The new method also is more specific, accurately detecting DNA even in the presence of unfavorable PCR products in the samples that may interfere with quantification results.