A new technique allows researchers to pick out mutations in a single base pair in a target stretch of DNA, according to a study funded by the National Institutes of Health, the National Science Foundation and the Department of Defense’s Advanced Research Projects Agency.

These probes allow researchers to look in much more detail for variations in long sequences of up to 200 base pairs; current methods can detect mutations in stretches of up to only 20.

The ability to look at a specific segment of DNA and pinpoint a single mutation could help diagnose and treat diseases. Researchers give the example of drug-resistant strains of tuberculosis; their new method makes it possible to check, as a preventive measure, for the specific genes containing mutations that prevent the patient from responding to treatment.

“We’ve really improved on previous approaches because our solution doesn’t require any complicated reactions or added enzymes, it just uses DNA,” said lead author Georg Seelig, a University of Washington assistant professor of electrical engineering and computer science. “This means that the method is robust to changes in temperature and other environmental variables, making it well-suited for diagnostic applications in low-resource settings.”