Scientists at Stanford University have disproved the “dumb blonde” stereotype with research that shows that hair color is not related to any other trait and does not affect intelligence, The Daily Mail reports.
Lead researcher Professor David Kingsley said, “The genetic mechanism that controls blond hair doesn’t alter the biology of any other part of the body. It’s a good example of a trait that’s skin deep, and only skin deep,” because it relies on a single letter of the genetic code.
By switching a letter, you could change a blonde to a brunette, and it would have no effect on the brain.
In experiments, the blonde gene, called Kit ligand, caused animals to be born with lighter fur. The brunette gene in animals with darker fur reduced Kit ligand activity by 20 percent.
“This is a good example of how fine-tuned regulatory differences may be to produce different traits,” Dr. Kingsley said.
Researchers also found that the Kit ligand gene does not affect eye color, so blonde hair and blue eyes are not genetically linked.