A little striped fish has helped scientists begin to solve one of
the biggest mysteries in biology — which genes are responsible for
differences in human skin, eye and hair color.
The large,
international team of scientists reported on Thursday that they had
found a gene that makes African zebrafish of a lighter-than-normal
color — and say the same gene helps explain the light-colored hair,
skin and eyes of many Europeans.
While they stress that they have
not found a genetic basis for race, they say just a tiny change in a
single amino acid plays a major role in causing the distinctive light
European coloring.
The gene is called SLC24A5, Keith Cheng of Pennsylvania State University and colleagues said.
"Our
results suggest that SLC24A5 explains between 25 and 38 percent of the
European-African difference in skin melanin index," they wrote in
Friday’s issue of the journal Science.
Cheng’s team was
originally looking for genes involved in cancer. They were using
zebrafish, a favored tool of genetic researchers because they are
small, reproduce quickly and are well understood.
They found a
gene that appeared to make some zebrafish "golden" — with
lighter-than-usual stripes. Under a microscope, the skin of these fish
have smaller, fewer structures called melanophores.
In people of
European descent, pigment granules called melanosomes are fewer,
smaller, and lighter than those from people of West African ancestry.
The melanosomes of East Asians fall in between.
This suggested gene variations may be responsible and may be similar in vertebrates — which include fish, mice and people.
By Maggie Fox
