Professor Alan Cooper spoke at BrisScience on his research on ancient DNA. He works at the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide.
One aspect of what they study is diseases. The dental calculus that builds up on teeth is the remains of the bacteria in the mouths of people. It is what the dentist cleans off our teeth.
On fossil teeth the dental calculus is a record of the germs that were in the mouths of the animal or person.
From these calcified bacteria it is possible to study the transition form hunter gatherer to farming and to modern people.
The startling thing is that the biggest impact BY FAR on our health is in the last 200 years (since the industrial revolution) with the introduction of SUGAR into our diets.
There is a LARGE change from medieval to today. As soon as sugar come into the diet the entire mouth bacteria change.
They are sort of the bacteria equivalent of weeds – a small number of dominant types that have bad effects on our health.
These are opportunistic pathogens and many are associated with HEART DISEASE. That’s right! The bacteria in our mouth that grow in the sugar in our diet play several roles in heart disease.
Firstly some of them deposit calcium in our heart arteries.
Secondly some of them lead to autoimmune responses that attack our heart valves.
Bacteria make 90-99% of us!!!
The other thing he said which is nothing to do with bacteria in our mouths is that humans have hybridized quite a few times and pretty well all the humans outside Africa are hybrids with Neanderthals about 1.3% Neanderthal!
He also talked about the Denosovans whose DNA was only found to the east of Wallace’s line. David Reich et all (2011) are studying the Aboriginal genome.
When humans moved from hunter gathering to farming their life became much tougher and they became much shorter. They had severely reduced nutrition bad teeth worn down by the grain a harsh life but they lived longer lives than the happier hunter gatheres because they could develop specialist skills.