Decontamination techniques in ancient DNA analysis

Contamination is one of the most troublesome aspects of ancient DNA analysis. Resulting from the ease with which samples may be contaminated, decontaminating ancient remains has become a necessary step in ancient DNA analysis. Unfortunately, there have been no controlled studies of the efficacy of current decontamination techniques. This study examined a variety of chemicals to test their effectiveness at removing DNA within solution. Bleach, being the most effective chemical destroyer of DNA, was subsequently tested in a controlled experiment using an artificial DNA fragment for contamination and an ancient animal proxy. Results indicated that submersion in 100% household bleach for 5 to 10 minutes was the most efficient technique for removing contaminant DNA on ancient bone surfaces. However, this treatment may not adequately decontaminate heavily and deeply contaminated bone samples since 100% bleach could not remove contaminant DNA that has been soaked into bone, even after 20 minutes of exposure.