[Paleopsych] NPR: Researchers Discover Skin Color Gene

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Researchers Discover Skin Color Gene
http://www.npr.org/templates/story/story.php?storyId=5055391

[This time we do get a warning about racism. No surprise, consider it's 
National Public Radio.]

[14]Nell Boyce

Zebrafish

Thanks to a mutation in a gene that controls skin pigmentation, the 
"golden" zebrafish has stripes that are much fainter than the black and 
white stripes of normal zebrafish. Now researchers have found a similar 
gene in humans.


[15]All Things Considered, December 15, 2005 · Scientists say they've 
found a gene that seems to partially control skin color. And they say that 
a small change in the gene could explain why people with European ancestry 
tend to have different coloring than people of African or Asian descent.

Scientist Keith Cheng says he got drawn into the emotionally charged field 
of race and genetics because of his interest in a small, tropical fish. 
"Of course I had trepidations," laughs Cheng, who is a cancer researcher 
at Penn State College of Medicine in Hershey, Pa. "But my curiosity 
overwhelmed my trepidation, and this amazing fact that this fish that was 
found in a pet store might inform us about skin color in a major way was 
just too much to resist."

Cheng normally studies genetic mutations that cause cancer, with the help 
of minnows called zebrafish. Usually zebrafish are white with black 
stripes. But there's also a "golden" variety that has much fainter 
stripes. Cheng noticed that the difference in skin pigmentation patterns 
between these two fish varieties seemed to mimic the pigmentation 
differences seen in people with either dark or light skin. It made Cheng 
wonder if he could use this fish to explore why people have different skin 
colors. "How can you not be curious about why an Asian might look 
different from a Caucasian or look different from an African person?" 
Cheng asks. "That's very interesting. You look different. Why is that?"

Cheng may have discovered part of the answer, with the help of his lab 
fish. His team discovered a skin pigmentation gene that, when mutated, 
causes the "golden" pattern in zebrafish. And then they looked for a 
similar gene in humans.

In the journal Science, his team reports that people do have a similar 
gene. In fact, there are two common versions. One showed up in almost all 
DNA samples taken from small groups of people living in Africa and Asia. 
The other version appeared in almost all of the people they tested who had 
European descent.

The researchers also used measurements of light reflection to evaluate 
skin coloration in a group of people with so-called mixed ancestry. "On 
average, and I need to point out on average, the variation correlates with 
skin color," says Cheng. People with the European version of the gene 
tended to have lighter skin.

Cheng and his colleagues say this information could be useful for studying 
skin cancer, or for finding new ways of changing skin color that wouldnt 
be as damaging as tanning.

But police officers are likely to be interested, too. Already, some 
officials are testing DNA left at crime scenes to get clues about what the 
culprit might look like. Tony Frudakis runs DNAPrint Genomics, a 
Florida-based company that uses gene markers associated with geographic 
ancestry to give police a general sense of whether someone might look more 
black or white. In one case, he says, such "DNAWitness" testing helped 
recently track down a serial killer in Louisiana.

"They had been targeting a Caucasian individual based on faulty eyewitness 
testimony," says Frudakis. "We showed that the samples found at the crime 
scene corresponded to someone who was of predominantly sub-Saharan African 
ancestry. So this sort of changed the profile of who they were looking 
for." He says his company has done this kind of testing for a wide variety 
of law-enforcement agencies, including those in places like New York, 
Chicago and Los Angeles.

Frudakis believes that this method of profiling could be improved by 
testing genes for more specific features like eye color or height. And he 
thinks this new gene for skin color is a step towards that goal. Other 
scientists agree that genes do control a lot of a person's appearance; 
identical twins are the perfect illustration.

But genetic experts emphasize that this new discovery about skin color is 
a long way from being able to use gene tests to reconstruct exactly what a 
person looks like. "Having or not having this particular variant will not 
allow you to say what shade that person's skin might be, within anything 
other than very wide limits," says Francis Collins, director of the 
National Human Genome Research Institute. That's because skin color is 
controlled by multiple genes.

And Collins also worries that people will confuse skin color with race. 
"This is most definitely, and let me emphasize this even more, not the 
gene for race, which is something I've heard a couple people already say 
when they heard about this result," Collins says. "There is no gene for 
race."

Collins says the social idea of race depends on all kinds of cues beyond 
physical appearance and skin color, everything from your neighborhood to 
your family traditions to your clothes. And thats what leads Pilar 
Ossorio, a scientist and lawyer at the University of Wisconsin, to 
question how useful genetic tests for skin color and ancestry will be for 
profiling crime suspects.

Consider this, Ossorio says: What if someone with a lot of genes for 
Native American ancestry and medium-brown skin speaks Spanish and lives in 
a Hispanic community? "That person could be living in the world as a 
Hispanic person and the police would probably not connect that Hispanic 
person with the profile that they got," she says. "We use a lot of things 
to understand what race someone is, what ethnicity they are, where they 
fit in our social world." And for most of them, she points out, there is 
no genetic test.

References

   14. http://www.npr.org/templates/story/story.php?storyId=4494969
   15. http://www.npr.org/templates/rundowns/rundown.php?prgId=2
   16. http://www.npr.org/templates/story/story.php?storyId=5055391#email