Blondes Have More . . . Brains?

According to a new study published in Nature Genetics blondes may not be as dumb as some classic jokes would have us believe. Scientists from Stanford University have discovered the secrets as to which specific variants lead to blond hair. The team learned that the alteration of just one letter of the genetic code creates lighter hair.

Specifically, the results indicate that an A (adenine) is switched to a G (guanine) on an area of human chromosome 12 it causes blond hair. The researchers stated that due to the fact that this particular genetic change affects only the hair follicle, other cell types â€" for example brain cells â€" are not influenced. In layman’s terms:  Blondes are not automatically dumb because of their hair color.  Being blond is “only skin deep.”

Hair color doesn’t make blondes dumb/Image: StickBoyDaily

Study author David Kingsley said: “We’ve been trying to track down the genetic and molecular basis of naturally occurring traits â€" such as hair and skin pigmentation â€" in fish and humans to get insight into the general principles by which traits evolve. Now we find that one of the most crucial signaling molecules in mammalian development also affects hair color.”

Previous genetic studies of people in the Netherlands and Iceland were the first indicators that a particular portion of DNA could be behind hair color. This aided the investigative team in theoretically pinpointing the single genetic change which they next tested on mice. The rodents with that one “nucleotide change” were found to possess lighter fur.

Scientists noted that the single gene in which the change occurs produces NITLG, a protein, which is reportedly “a stem cell factor” and is accountable for numerous functions depending on where it is indicated. When the ‘switch” that causes blond hair happens, it has no influence on anything other than hair follicles. It has no effect on how the gene is revealed anywhere else.

The research team thinks knowing how this one change in this “junk” area of DNA can influence other traits could provide them with information on the purposes of these areas “in disease states.” Furthermore, the data demonstrates that the genetic change responsible for blond hair has nothing to do with eye or skin color either. Perhaps what is most important to blondes, however, is the fact that the change has nothing to do with intelligence.

Kingsley commented: “What we’re seeing is that this regulatory region exercises exquisite control over where and how much, KITLG expression occurs. In this case, it controls hair color. In another situation â€" perhaps under the influence of a different regulatory region â€" it probably controls stem cell division. Dialing up and down the expression of an essential growth factor in this manner could be a common mechanism that underlies many different traits.”

He concluded: “It’s clear that this hair color change is occurring through a regulatory mechanism that operates only in the hair. This isn’t something that also affects other traits, like intelligence or personality. The change that causes blond hair is, literally, only skin deep.”

Blondes Have More . . . Brains?