Each year, we celebrate National DNA Day on April 25. It’s a day that Congress and the National Human Research Institute set aside to:
- celebrate the anniversary of the Human Genome Project’s achievement,
- share the latest advances in genomic research with the public and
- let people see how those advances can improve their daily lives.
DNA From a Tooth
What many people may not realize is that teeth are one of the most durable and revealing sources of DNA available. Lodged in the jaw bone, the pearly whites remain somewhat protected. Dental pulp and dentin—key DNA repositories—lie safely covered in enamel. Plaque and saliva also play a role. For researchers, dental DNA offers invaluable data for decoding many of life’s greatest mysteries—past, present and future.
In difficult criminal or legal investigations, forensic odontologists may be the only people able to conclusively identify someone’s remains. Particularly in cases where many people are involved—like airplane crashes or disasters—teeth are often one of the most reliable sources of uncompromised, usable DNA. In the past, personal identification relied on:
- dental records,
- postmortem reconstructions or
- dental profiling.
However, dental DNA is far more accurate in establishing someone’s identity as long as a predeath DNA sample is available for comparison
When examining remains at ancient sites, researchers have found that both the dentin within teeth as well as the calcium plaques that form on them can be rich sources of DNA. In one particularly exciting joint study published in the American Journal of Physical Anthropology, researchers looked specifically at tooth calculus—plaque—on the 700-year-old remains of six Native Americans in Illinois. Surprisingly, the calculus
- yielded DNA for all six individuals examined—even for three whose bones held no DNA material.
- contained “DNA not only from the human but also the microbiome and the diet.”
In fact, “[n]o other material in the archaeological record contain[ed] so much DNA.” Who would have thought that dental DNA from plaque would allow researchers to “trace the history of the human species and provide glimpses at population movements” across the globe?
For those of us alive and in the present, science is even more focused on using genetics to
- learn why dental health varies so widely among people
- identify the causes of dental problems and diseases and
- create effective ways of treating or preventing them.
Saliva is proving helpful. It contains both human DNA and the DNA of any bacteria that live in the mouth. Researchers are examining both
- dental heredity and genetic predisposition to diseases like periodontitis and
- the effects of certain pathogens like bacteria that cause gingivitis or oral cancers, for example.
National DNA Day
DNA is indeed the language of life. The Human Genome Project proved it in 2003. Since then, every day brings still more enlightening discoveries at the molecular level. The applications for dental DNA extend from forensics and archaeology to dentistry, medicine and beyond. National DNA Day reminds us all of our shared humanity and the fact that the answers to so many of science’s questions lie within us.