California Sea Grant College Program

Biology professor Dr. Clifford F. Brunk at UCLA, and colleagues isolated DNA from bacteria in water samples. They then used a polymerase chain reaction (PCR) analysis to amplify the genetic information of several small subunits of ribosomal RNA genes. From these, the scientists identified a set of nine genetic markers that made it possible to "fingerprint" the bacteria and so identify its source. The researchers found genetic markers that distinguish storm drain runoff from sewage effluent and human from animal feces.