Not-so-dizzy blondes! Hair myth busted

Blondes have long been the subject of wisecracks regarding their IQ. However, scientists have finally disproved the dumb blonde bimbo stereotype. New research has revealed that hair colour is actually ‘skin deep’, as it depends on just a single letter of the genetic code.

According to scientists at California’s Stanford University, switching a single ‘letter’ of DNA would turn brunettes to blondes – and would have no affect on the brain.

The Stanford study proves that hair colour is completely unrelated to any other trait, and dispels the shallow (but fairly popular) claim that blonde hair signifies lower intelligence.

Lead researcher of the study 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.’

The academics also discovered that the gene that affects blonde hair isn’t associated with eye colour. This suggests that blonde hair and blue eyes are not genetically linked.

The researchers carried out experiments with mice which revealed that the ‘blonde’ switch caused animals to be born with light, golden-brown fur.

The switch alters activity of a gene known as ‘Kit ligand’, which was already known to be associated with hair colour.

Compared with its ‘brunette’ version, which has a different DNA letter, the blonde switch reduced Kit ligand activity by about 20%.

Dr Kingsley, whose research appears in the journal Nature Genetics, said: ‘This is a good example of how fine-tuned regulatory differences may be to produce different traits.’