Rethinking How We Do DNA Testing of Ancient Humans

dna-testing-for-ancient-rootsIt isn’t as easy to do DNA testing on ancient bones as CSI and other television shows makes it look. Most probably have the idea that an Indiana Jones type just snaps everyone into shape in the lab, and the results are whipped up magically. Why would anyone think that? Genetic testing has become so advanced and so routine in our everyday lives. However, genetic testing of ancient bones is a much more difficult process.

What is the difference? Contamination is more likely. When genetic testing is done by a professional, certified ISO lab, chances of contamination are next to impossible as proper procedures are followed. No matter the type of genetic testing one has, very careful steps are part of the process to ensure contamination does not happen for most modern day medical and genetic testing. If proper standards are followed, that is not a problem. Your DNA is sitting in a container, nice and secure, before it is analyzed. The DNA of an ancient human is sitting in dirt and has been for many thousands of years. This means the DNA has often largely been broken down and degraded in warm soil where bacteria have made a cozy home (Jocelyn Kaiser, Science, and “Cleaning up Ancient Human DNA”).

Of course, there are exceptions, but the conditions are exceptional. The difference is found in cold conditions versus warm ones. There have been cases of “human DNA samples taken from human bone, tooth, hair, or other tissue typically preserved in frozen soil, ice, or a chilly cave” like “Otzi the 5300-year-old iceman and even Neanderthals.”

That isn’t the norm, however, and we cannot change the conditions the DNA has undergone that we find because we want the best DNA testing results. So how do we fix the problem of genetic testing of bones and other human remains that are found in less than optimum conditions? It is usually an expensive process, but scientists are thinking of ways they can filter away the “non-human DNA.” Then the bones can tell us more stories about where they are from. For instance, using this method a team determined a “500-year-old Peruvian mummy did not have European ancestry as claimed” (Kaiser).

Cleaning ancient bones using this method will mean better DNA testing results despite bad conditions. And it just might mean that we can use whole genome sequencing on samples that we did not think possible before (Meredith L. Carpenter et al, American Journal of Human Genetics, “Pulling out the 1%- Whole Genome Capture”).  What does this mean? If we are able to get better results from Neandertals, from Denisovans, from the little ancient hobbit-like people of Indonesia called the Homo Floresiensis, we might have a better picture of our origins as well as other hominins and how we connect to those different hominins. We would have a clearer story.

Check if you want to discover your ancient roots.

13 May 2014 | 1:14 pm – Source:

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