Dry earwax? It's genetic
Genetics researchers have uncovered the key gene behind the mystery of human earwax.
Finally.
The report in Monday's Nature Genetics journal solves a long-running anthropologist's riddle - why many people in China and Korea, as well as elsewhere in Asia, have dry earwax while the rest of humanity enjoys the sticky variety.
The finding could represent the leading edge of some new reports about non-disease-related genes that are responsible for visible changes in human anatomy, population researchers say.
Geneticists had known the neighborhood of the earwax gene from previous work and decided to pin it down. The earwax riddle surprisingly comes down to a single gene, dubbed ABCC11, reports a Japanese team led by Koh-ichiro Yoshiura of the Nagasaki University Graduate School of Biomedical Sciences. The gene comes in two types, or alleles, corresponding to wet or dry earwax.
By examining 126 Japanese volunteers, the team determined that the dry-earwax gene is recessive, meaning both parents must pass a copy to their children for it to work. To chart a global earwax gene map, the team next looked at volunteers from 33 populations worldwide, from Native Americans to Ashkenazi Jews to Polynesian islanders. The dry-earwax allele probably arose "in northeast Asia and thereafter spread throughout the world," the team concludes.
"These results are amazing," says biological anthropologist Mark Shriver of the Pennsylvania State University in University Park by e-mail. Shriver says the Japanese team's success points the way to future finds of disease-related genes specific to certain populations worldwide, as well as glimpses of how evolution changes genes in people over time.
"We should recognize that we really know very little right now and embrace any chance to learn about how the forces of evolution have shaped human biology," he says.
In December, Shriver and colleagues, led by geneticist Keith Cheng of the Pennsylvania State University College of Medicine in Hershey, identified a gene responsible for much of the difference in human skin color between Europeans and Africans. Other genes probably govern skin hues elsewhere.
Taken with the earwax find, the trend is toward genetic research finding more of the non-disease genes responsible for physical differences in people worldwide, says anthropologist Joanna Mountain of Stanford University in Palo Alto.
"We're all curious what makes people different," she says.
Mountain suggests the dry-earwax allele probably originated within the past 30,000 years, "or even much more recently."
Intriguingly, the dry-earwax gene turns up fairly often in Native Americans, in about 30% of a sample of that population.
That suggests the emigrants from Asia who first populated North and South America brought the gene with them, the Japanese team says.
Dry earwax may have given people in northeast Asia some advantage during past periods of cold climate, not freezing as readily, the researchers suspect,
But "this is still pretty speculative," Mountain says.
Finally.
The report in Monday's Nature Genetics journal solves a long-running anthropologist's riddle - why many people in China and Korea, as well as elsewhere in Asia, have dry earwax while the rest of humanity enjoys the sticky variety.
The finding could represent the leading edge of some new reports about non-disease-related genes that are responsible for visible changes in human anatomy, population researchers say.
Geneticists had known the neighborhood of the earwax gene from previous work and decided to pin it down. The earwax riddle surprisingly comes down to a single gene, dubbed ABCC11, reports a Japanese team led by Koh-ichiro Yoshiura of the Nagasaki University Graduate School of Biomedical Sciences. The gene comes in two types, or alleles, corresponding to wet or dry earwax.
By examining 126 Japanese volunteers, the team determined that the dry-earwax gene is recessive, meaning both parents must pass a copy to their children for it to work. To chart a global earwax gene map, the team next looked at volunteers from 33 populations worldwide, from Native Americans to Ashkenazi Jews to Polynesian islanders. The dry-earwax allele probably arose "in northeast Asia and thereafter spread throughout the world," the team concludes.
"These results are amazing," says biological anthropologist Mark Shriver of the Pennsylvania State University in University Park by e-mail. Shriver says the Japanese team's success points the way to future finds of disease-related genes specific to certain populations worldwide, as well as glimpses of how evolution changes genes in people over time.
"We should recognize that we really know very little right now and embrace any chance to learn about how the forces of evolution have shaped human biology," he says.
In December, Shriver and colleagues, led by geneticist Keith Cheng of the Pennsylvania State University College of Medicine in Hershey, identified a gene responsible for much of the difference in human skin color between Europeans and Africans. Other genes probably govern skin hues elsewhere.
Taken with the earwax find, the trend is toward genetic research finding more of the non-disease genes responsible for physical differences in people worldwide, says anthropologist Joanna Mountain of Stanford University in Palo Alto.
"We're all curious what makes people different," she says.
Mountain suggests the dry-earwax allele probably originated within the past 30,000 years, "or even much more recently."
Intriguingly, the dry-earwax gene turns up fairly often in Native Americans, in about 30% of a sample of that population.
That suggests the emigrants from Asia who first populated North and South America brought the gene with them, the Japanese team says.
Dry earwax may have given people in northeast Asia some advantage during past periods of cold climate, not freezing as readily, the researchers suspect,
But "this is still pretty speculative," Mountain says.
posted by Ubiquitin at 7:42 PM
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