Washington: Chimps and
humans share a whopping 96 percent genetic similarity --
surprisingly the simians rarely develop cancer, while their human
cousins are particularly vulnerable.
Georgia Tech's Soojin Yi, a biologist, looked at brain samples of
the two species. She found that differences in the modification of
certain DNA, called methylation, may contribute to such changes.
The results also hint that this process of DNA modification plays
an important role in some disease-related phenotypes (composite of
an organism's observable characteristics or traits) in humans,
including cancer and autism, the American Journal of Human
"Our study indicates that certain human diseases may have
evolutionary epigenetic (the effect of environment on genes)
origins. Such findings, in the long term, may help develop better
therapeutic targets or means for some human diseases," says Yi,
according to a Georgia Tech statement.
Yi and her team generated maps of modified DNA of the prefrontal
cortex (front part of the brain, tied to personality, decision
making and moderating social behaviour) of multiple humans and
chimps. They found hundreds of genes (among humans) that "include
disproportionately high numbers of those related to diseases,"
"They are linked to autism, neural tube (brain and spinal cord)
birth-related defects and alcohol and other chemical
dependencies," said Yi.