Increased DNA amplification success of non-invasive genetic samples by successful removal of inhibitors from faecal samples collected in the field

Abstract

The use of non-invasive genetic sampling (NGS) is becoming increasingly important in the study of wild animal populations. Obtaining DNA from faecal samples is of particular interest because faeces can be collected without deploying sample capture devices. However, PCR amplification of DNA extracted from faeces is problematic because of high concentrations of inhibitors. Here we present a method for increasing the successful application of donor DNA extracted from faecal samples through inhibitor reduction. After standard extraction with a DNA stool kit we used a ‘Concentrated Chelex Treatment’ (CCT) that increased the amplification success from 31.7 to 61.4% of loci. Our results suggest that darker supernatant and samples with more precipitate contain more inhibitors than lighter samples and samples with little or no precipitate. We expect the use of this technique to have wide applicability within conservation biology for research and management that relies on NGS of wild animal populations.