USGS Analyst Performs DNA Extractions in a Laboratory

A U.S. Geological Survey analyst performs DNA extractions on enriched cultures of water from the study area. Once the DNA was extracted it was used to detect pathogen gene markers using polymerase chain reaction (PCR). Scientists have found that the presence of indicator bacteria, hepatitis E virus (HEV), and numerous bacterial pathogen genes increased following precipitation-induced runoff events in streams draining adjacent land surfaces in Iowa where swine manure was recently applied.