A study of evolution over the past 7,500 years has shown that today a person has a more monotonous microflora in his mouth than his ancient ancestors.

Scientists are sure that this is the cause of chronic diseases of the oral cavity, often found in industrialized countries.

Researchers from the Australian Center for the Study of Ancient DNA (ACAD) at the University of Adelaide, as well as their colleagues from the University of Aberdeen (Scotland) and the WTS Institute (Cambridge, England) published their results on the pages of "Nature Genetics".

The authors say that the analysis of the DNA of petrified bacteria on the teeth of our ancestors "helped shed light on the changing diet for thousands of years and the consequences of this change for health". They argue that as the person moves from hunting and gathering to farming, our diet deviates significantly from the norm that is characteristic of primates. This led to a violation of the microflora of the oral cavity and the appearance of chronic diseases. The industrial revolution further exacerbated the state of affairs.

Professor Alan Cooper, director of ACAD and head of research, said: "This is the first study in the world that sheds light on how evolution affected our microflora. We have proved that in modern humans the microflora of the mouth is not as diverse as in ancient people. This can be directly related to the development of chronic gum disease, which often affects people in developed countries ".

During the study, scientists extracted DNA from bacteria from the calcified plaque of 34 ancient people whose remains were found in northern Europe. They studied the changes in the composition of the microflora of the oral cavity over the past millennia and compared these results with modern.

Dr. Christina Adler, co-author of the study and co-author of the University of Adelaide, commented on the study: "Genetic plaque analysis helps to create a detailed archive of dietary effects on the evolution of the microflora of the oral cavity and health, which gives tremendous opportunities for researchers".

Professor Cooper says: "With the advent of agriculture, the microflora of the human mouth has changed significantly, and new abrupt changes occurred about 150 years ago. This was due to the spread of sugar and flour, which led to the rapid suppression of beneficial bacteria and the prosperity of pathogenic microbes. The cavity of the mouth of a modern person is constantly in an unhealthy state ".

Professor Cooper collaborated with Professor Keith Dobney of the University of Aberdeen, studying this issue for the past 17 years. Professor Dobney states: "We tried to identify the types of prehistoric bacteria that were in the dental plague of ancient people, but without success. These are the bacteria that we lost over the centuries of evolution. Ancient DNA probably contains an answer ".

Professor Dobny says that the study gives an idea of ??how the previous generations of people lived and died.

If we know the true genetic history of the diseases that people are suffering from today, we can better understand them and treat them more effectively.

It should be noted that until 2007 scientists could not properly monitor the level of bacterial contamination. This became possible thanks to the new ultra-clean ACAD laboratories and the use of the latest research equipment. Now scientists are able to trace the geographical and chronological changes of bacterial microflora, which will help modern biology and medicine.

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