Whoever heard of finding ancient human DNA by sifting through clay and sand? The way scientists studied the genes of ancient humans was to recover DNA from fossil bones, which was hard to find since genetic material is scarce. Looking for DNA in sediment, rather than just finding fossils, has opened up the study of ancient DNA to a broader range of analysis to understand not just a single organism but groups and patterns using more sources such as gene fragments that can be found in the natural world around us. With the new methods to find DNA, we are no longer limited to finding large quantities of ancient specimens. Modern genetic analyses can help us get there even with low-quality DNA dating back several thousand years.
The study of ancient DNA uses the polymerase chain reaction that generates many millions of copies of a particular target sequence of DNA. It enables the amplification of a specific DNA fragment from a few intact DNA molecules. In working with ancient DNA, strict procedures must be followed to limit contamination because it can occur during DNA extraction. “The survival of ancient DNA appears to be influenced less by the age of specimen than by environmental conditions under which it was preserved.”
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Kolkata, Gina. “No Bones About It: Scientists Recover Ancient DNA From Cave Dirt.” New York Times (New York, NY), April 27, 2017. Accessed July 27, 2017. https://www.nytimes.com/2017/04/27/science/ancient-human-dna-cave-dirt.html?mtrref=undefined&gwh=5641D41C7526C503C019E5557958AE28&gwt=pay.