Recovery of DNA from Teeth Exposed to Variable Temperatures

Abstract

In mass disaster situations, human remains are often subjected to extreme conditions, and identification by traditional anthropological means may need to be supplemented by DNA analysis. In extreme cases, bones and teeth are potentially the only viable source of DNA. The present research evaluates the correlation between the taphonomic state and the quantity and quality of nuclear DNA obtained from thermally altered teeth. This study used an extraction procedure involving the use of a demineralization extraction buffer followed by concentration and purification. After heat exposure, each tooth was assigned a color value of 1 to 5 to score the state of combustion of the sample. The results indicate a strong correlation between the quantity of DNA recovered, the quality of the DNA obtained, and the color value. The highest recovery rates and lowest degradation index values were obtained from teeth assigned a color value of 1 (unaltered beige) or 2 (yellow to orange). These teeth were exposed to room temperature, 100°C, or 200°C. At temperatures exceeding 200°C, the amount of DNA recovered drastically decreased or was undetected, indicating that DNA processing of thermally altered specimens should be limited to samples with beige, yellow, or orange post-burn coloration. Samples that are brown, black, or gray in coloration (carbonizing to calcining) will likely provide low or undetectable DNA quantification results and little information as to the identity of the remains.