Scientists from the Southern California Coastal Water Research Project Authority (SCCWRP) outlined the advantages of digital polymerase chain reaction (dPCR) over real-time quantitative PCR (qPCR) at a conference hosted by the Environmental Protection Agency’s Office of Science and Technology early this year in Louisiana.
Real-time qPCR is increasingly being used for ambient water monitoring, but development of dPCR has the potential to further advance use of molecular techniques in such applications, according to Yiping Cao, John F. Griffith and Stephen B. Weisberg of SCCWRP who authored the poster entitled, “The Next Generation PCR-based Quantification Method for Ambient Waters: Digital PCR.”-endpar-
Mr. Griffith and Mr. Weisberg, who presented at the conference, explained that qPCR quantifies a sample indirectly based on interpolation from standard curves and the assumption that sample and reference DNA amplify at the same speed/efficiency. Digital PCR, on the other hand, quantifies a sample directly by counting frequency of positives among the thousands/millions of miniature partitions of the sample itself.
Source Molecular Corporation is now offering digital PCR service, which SCCWRP says is “uniquely suited for ambient water monitoring” because of its higher tolerance to inhibition, higher nominal sensitivity, higher precision especially at low target concentrations compared to qPCR. Source Molecular helps organizations struggling with water pollution, particularly fecal contamination.
The greater the accuracy of the test, the more it is helpful for watershed managers seeking to understand the source of the fecal pollution and how concentrated the pollution is in the water. It leads to greater credibility and better crafted remediation plans that result in savings to affected organizations.
Source Molecular is very familiar with implementing the dPCR technology. Source Molecular had worked with SCCWRP when SCCWRP conducted an inter-laboratory research study on the use of dPCR to monitor environmental contaminants in water.
Aside from its dPCR service, Source Molecular also offers patented tests from the EPA for Human, Cattle, Chicken and Dog fecal pollution. It is currently the only commercial license holder offering these tests to the market. All in all, Source Molecular’s laboratory can provide analysis on 23 different tests from 13 different hosts — Human, Cattle, Swine, Gull, Goose, Chicken, Dog, Deer, Elk, Horse, Bird, Ruminant and Beaver.