With the help of DNA sequencing, scientists have shown that human DNA can be enriched from calcified dental plaque. In fact, they've now managed to reconstruct mitochondrial genomes from ancient specimens for maternal ancestry analysis.
Calcified dental plaque, also known as dental calculus, has recently been shown to be an important source for researchers to gather ancient DNA from dietary and microbial sources. Now, though, researchers have found that it could also be an important source for ancient human DNA.
Dental calculus is preserved alongside human, skeletal remains. However, it's not actually a human tissue. Also known as tartar, dental calculus is a calcified form of dental plaque that acquires human DNA and proteins passively through saliva and other host secretions. Once this DNA is trapped within the tartar, though, it can be preserved for thousands of years.
In this latest study, the researchers used dental calculus to see if they could extract human DNA. In this case, they looked at remains from the Oneota, which was a Native American archaeological culture that rose to its height sometime between 1000 and 1650 AD, but quickly declined after its contact with Europeans.
The scientists found that they needed very little dental calculus for analysis. In fact, they needed fewer than 25 milligrams per individual. This means that the researchers can get high quality genetic ancestry information from very little material, which is a huge boon when it comes to the examination of archaeological remains.
"Dental calculus may enable researchers to retrieve ancient DNA from samples where bone or other biological tissues are too degraded for analysis," said Maria Nieves Colón of Arizona State University, one of the researchers involved in the study. "This is particularly exciting to those of us who work in tropical or extremely old contests, where traditional sources of DNA may be poorly preserved or even non-existent."
With the help of dental calculus, researchers can reconstruct whole mitochondrial genomes. This is huge when it comes to better understanding ancient humans and their culture, and it may also reveal a bit more about migration patterns and where their current descendants are today.
The findings were published in the March 16 issue of the American Journal of Physical Anthropology.
