Polymerase Resistance to Polymerase Chain Reaction Inhibitors in Bone*

Abstract

Amplification of DNA from aged or degraded skeletal remains can be a challenging task, in part due to naturally occurring inhibitors of the polymerase chain reaction. PCR inhibitors may act by inactivating a polymerase itself, or compete with or bind other reaction components, although various polymerases may be differentially susceptible to such insult. In this study, ten thermostable polymerases from six bacterial species were examined for their ability to amplify DNA in the presence of bone-derived or individual PCR inhibitors. Two polymerases, one from Thermus aquaticus and one from Thermus thermophilus, showed lower susceptibility to inhibition from bone, while polymerases from Thermus flavus were highly susceptible. Addition of bovine serum albumin improved the activity of most of the enzymes. Taken together, the results indicate that thermostable DNA polymerases have different susceptibility to bone-derived PCR inhibitors, and that those most often used in forensic laboratories may not be optimal when working with DNA from skeletal remains.