Could a predisposition to itchy psoriasis and Crohn's disease have actually given our ancestors a genetic benefit?
New research suggests genetic links to modern maladies are more ancient than we thought, and may have even acted as evolutionary advantages, the University at Buffalo reported.
"Our research shows that some genetic features associated with psoriasis, Crohn's disease and other aspects of human health are ancient," said senior scientist Omer Gokcumen, a University at Buffalo assistant professor of biological sciences.
To make their findings the researchers compared modern human genomes to those of primates and ancient humans. They pinpointed chunks of DNA that exist in chimpanzees but that were later erased through evolutionary processes (called "deletion), and the functionality of these deletions varied among humans and ancestors such as the Neanderthals and Denisovans.
Certain traits, such as predisposition to disease, are often thought of as "good" or "bad"; these new findings highlight the idea that this concept is not as black and white as people make it out to be. For example, sickle cell anemia can cause illness in humans, but the curved cells caused by the disease are also less susceptible to parasites such as those that cause malaria.
"Crohn's disease and psoriasis are damaging, but our findings suggest that there may be something else -- some unknown factor now or in the past -- that counteracts the danger when you carry genetic features that may increase susceptibility for these conditions," Gokcumen said. "Both diseases are autoimmune disorders, and one can imagine that in a pathogen-rich environment, a highly active immune system may actually be a good thing even if it increases the chances of an auto-immune response."
The findings were published in a recent edition of the journal Molecular Biology and Evolution.
