A method for the temperature-controlled extraction of DNA from ancient bones

Contamination with microbial and other exogenous DNA poses a significant challenge in the generation of genome-wide sequence data from ancient skeletal remains. Here we describe a method for separating ancient DNA into multiple fractions during DNA extraction by sequential temperature-controlled release of DNA into sodium phosphate buffer. An evaluation of the effectiveness of the method using a set of three ancient bones resulted in between 1.6- and 32-fold enrichment of endogenous DNA compared with regular DNA extraction. For two bones, the method outperformed previous methods of decontaminating ancient bones, including hypochlorite treatment, which resulted in near-complete destruction of DNA in the worst-preserved sample. This extraction method expands the spectrum of methods available for depleting contaminant DNA from ancient skeletal remains.