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Researchers Pinpoint Human Skin Color Gene

BY Admin  December 19, 2005 at 12:30 PM EST

The work, published Friday in the journal Science, suggests that the skin-whitening mutation occurred by chance in a single individual after the first humans left Africa — when all people were brown-skinned — and migrated into Europe, reported the Washington Post.

An international team of scientists led by Keith Cheng of Pennsylvania State University reported that they had found a gene that makes African zebrafish of a lighter-than-normal color, and the same gene, called SLC24A5, may help explain the light-colored hair, skin and eyes of many Europeans.

The gene appeared to make the fish golden with lighter-than-usual stripes. Under a microscope, the skin of the fish had smaller, fewer structures called melanophores.

In people of European descent, pigment granules called melanosomes are fewer, smaller and lighter than people from West African ancestry. The melanosomes of East Asians fall in between, according to Reuters.

“It’s a major finding in a very sensitive area,” said Stephen Oppenheimer, an expert in anthropological genetics in Oxford University, who was not involved in the study, the Post reported. “Almost all the differences used to differentiate populations from around the world really are skin deep.”

More than 100 genes are involved in pigment production, but most of the genes identified so far have been found in unusual conditions, such as albinism, which causes very light skin and eyes.

Researchers have published maps of the human genome, and Cheng’s team made use of them, zeroing in on SLC24A5. Pennsylvania State University pharmacologist Victor Canfield found that all vertebrates have a version of the gene, Reuters reported.

“Working out the details of pigmentation with help from model systems like zebrafish is a great paradigm for seeking understanding of other complex diseases such as diabetes or heart disease,” Cheng said in a statement.

Genetic researchers favor using zebrafish because they are small, reproduce quickly and are easily understood.