London, Feb 24 (IANS): Despite major changes in human diet and hygiene over the years, bacteria that cause gum disease - from mild to severe - today did the same to our ancestors 1,000 years ago!

Researchers found an ancient human oral cavity that carried numerous opportunistic pathogens and discovered that periodontal disease or gum disease is caused by the same bacteria today as in the past.

The dental calculus (plaque) preserved bacteria and microscopic particles of food on the surfaces of teeth - effectively creating a mineral tomb for microbiomes.

“The ancient human oral microbiome already contained the basic genetic machinery for antibiotic resistance more than eight centuries before the invention of the first therapeutic antibiotics in the 1940s,” claimed Christina Warinner from University of Zurich, Switzerland.

The scientists also recovered dietary DNA from ancient dental calculus, allowing the identification of dietary components, such as vegetables, that leave few traces in the archaeological record.

The researchers applied shotgun DNA sequencing to dental calculus for the first time.
They reconstructed the genome of a major periodontal pathogen and produced possibly the first genetic evidence of dietary biomolecules to be recovered from ancient dental calculus.

“Dental calculus is a window into the past and may well turn out to be one of the best-preserved records of human-associated microbes,” added professor Christian von Mering, from Swiss Institute of Bioinformatics.

The study has far-reaching implications for understanding the evolution of the human oral microbiome and the origins of periodontal disease.

According to professor Frank Ruhli from centre for evolutionary medicine at University of Zurich, “The study of ancient microbiomes helps us understand the evolutionary history of human health and disease”.

The research was led by University of Zurich, University of Copenhagen and University of York.

Today, moderate to severe gum disease affects more than 10 percent of the world's population and is linked to cardiovascular disease, stroke, pulmonary disease and type 2 diabetes, said the research published in the journal Nature Genetics.