Ancient DNA and Disease

Ancient deoxyribonucleic acid (DNA) may be thousands of years old with significant degradation from environmental exposure, as is typical for DNA from archaeological samples, or it may be only a few years old yet fragmented and damaged, such as found in formalin-fixed paraffin embedded medical samples. In the archaeological record, there are two primary sources of microbiome data: dental calculus preserves DNA of the oral microbiome, while coprolites and latrine sediments provide a window into the gut microbiome. Some pathogens, including those causing the mycobacterial diseases tuberculosis (TB) and Hansen's disease, as well as treponemal diseases such as yaws, bejel, and syphilis, can result in characteristic changes to the skeleton in those with chronic disease. The recovery and analysis of ancient TB DNA are facilitated by focusing on such individuals, but can be challenging because of the many species of environmental mycobacteria found in soil and water that can contaminate samples.