Neisseria gonorrhoeae bacteria may have driven the evolution of human gene variants that protect against dementia.
Photo credit: National Institute of Allergy and Infectious Diseases,
National Institutes of Health
Did Gonorrhea Give Us Grandparents?
In an
earlier study, researchers at the University of California - San Diego (UCSG), showed that a set of mutant genes help protect older adults against cognitive decline and dementia. Now the same team has shown that we may have evolved with these mutation as an evolutionary adaptation to the sexually-transmitted disease organism,
Neisseria gonorrhoeae that causes gonorrhoea.
These mutations are only found in
Homo sapiens and not in our close extinct relatives, Neanderthals and Denisovans, who share the same genes with our common ancestors, the chimpanzees, suggesting that these mutations only became widespread in the
H. sapiens genome after we split from our common ancestor with Neanderthals and Denisovans (possibly
H. erectus) a few hundred thousand years ago.
The implication of that is that having adults that survived longer and who could be actively involved in child-care of their grandchildren, may have been what gave us an advantage over the archaic hominins we came into contact with, both in Africa and in Eurasia.
The finding is an example of how a mutation which became fixed in the species genome in response to environmental pressure can then be adapted further for an entirely different purpose. The research also shows how the scientists were in no doubt at all about the power of the Theory of Evolution by Natural Selection to explain what we observe in biology. There is no sign of even a shadow of doubt about the TOE or any sign that the TOE is a theory in crisis, as Creationist frauds are continually telling their credulous dupes. The TOE is fundamental to any understanding of biology for anyone who knows anything about it.
Here is how the research is explained in the UCSG news release: