Preserved on ancient teeth, a fossilized microbial world is discovered
Scientists have discovered the DNA of millions of tiny organisms entombed in the ancient dental plaque of four medieval skeletons.
The findings, published in the journal Nature Genetics, have implications for research into what our ancestors ate, how they interacted, and what diseases they fought, the authors write.
"I feel like we discovered a time capsule that has been right under our noses this whole time," said Christina Warinner, a molecular anthropologist and the lead author of the study. "This is a game changer."
New understandings
Calcified plaque is the rough, bumpy stuff you might notice coating your teeth if you have skipped too many dental appointments. Today, dentists scrape plaque off our teeth as part of our regular dental cleanings, but before the days of modern oral care, it could grow layer upon layer until sometimes the hard plaque covering a tooth was thicker than the tooth itself.
The layers of calcified plaque entomb the bacteria that also live in our mouths -- turning them into small fossils even when we are alive. And when we die, these dense, calcified micro-fossils remain intact.
Throughout most of the history of archaeology, researchers have considered calcified plaque disposable -- often removing it from skeletons in the process of cleaning them. But recently, it has become clear that calcified plaque is a reservoir of information.
"People are realizing that you have this rich bacterial community living on the surface of your teeth..." [Matthew] Collins, [a co-author on the paper,] said. "There is so much information there. The challenge is how to access it."
Over the last decade scientists had started to look at ancient plaque samples under a microscope, hoping to find microscopic bits of food stuck in its hard matrix. But Warinner wanted to know whether it had also preserved DNA.
mms://203.69.69.81/studio/20140813ada7edb80272220ec684ebbf3e67391517874732a9eb7b5dc22f7a40b57c28a2d71.wma
No comments:
Post a Comment