The Journal of Young Investigators: An Undergraduate, Peer-Reviewed Science Journal
Volume 20, Issue 3. September 2010
Earwax Impressions
This person of European descent is most likely to have wet, gooey earwax. Now scientists know why. Image courtesy of iStockphoto.
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10 February 2006 -
While scientists search for genes that cause life-threatening illnesses, a less-prominent gene was recently characterized by a team of Japanese researchers: the gene that controls earwax. Their finding was reported in the journal, Nature Genetics.
Earwax comes in two different forms: wet or dry. In either form, it keeps dust and insects from entering the ear. While type of earwax plays an inconsequential role in affecting evolutionary fitness, it does indicate a difference between ethnic groups. Most importantly, the discovery of the single master earwax gene and its two alleles is a demonstration of the power of bioinformatics: the computerized analysis of biological data.
The Japanese researchers, led by Koh-ichiro Yoshiura of Nagasaki University, have studied the gene in 33 ethnic groups across the world. The wet form of earwax is predominantly found in Africa and Europe, where 97 percent of the people have it, and the dry form among East Asians and Native Americans. South and Central Asia is split roughly equally along earwax type.
The researchers pinpointed the gene as the ATP-binding cassette C11 gene. The researchers found that the dry type results from deactivation of the gene due to a single nucleotide polymorphism (SNP), a single change in the DNA sequence where a guanine (G) is replaced with an adenine (A). People who inherit the allele that has an A from both parents have dry earwax. Those who carry two of the alleles with G, or one G and one A, have wet earwax, making it the dominant form.
The researchers hypothesize that the original form was the wet type with the dry type originating somewhere in northern Asia. The dry form is quite common in Native Americans, providing a strong genetic link to the theory that their ancestors migrated across the Bering strait from Siberia 15,000 years ago.
Dr. Dr Sally Dawson, a lecturer in molecular audiology at University College London, UK, told the BBC News website: “This research has shown that this genetic analysis offers a method of studying how different populations moved around - such as how people may have arrived in North America.”
Earwax comes in two different forms: wet or dry. In either form, it keeps dust and insects from entering the ear. While type of earwax plays an inconsequential role in affecting evolutionary fitness, it does indicate a difference between ethnic groups. Most importantly, the discovery of the single master earwax gene and its two alleles is a demonstration of the power of bioinformatics: the computerized analysis of biological data.
The Japanese researchers, led by Koh-ichiro Yoshiura of Nagasaki University, have studied the gene in 33 ethnic groups across the world. The wet form of earwax is predominantly found in Africa and Europe, where 97 percent of the people have it, and the dry form among East Asians and Native Americans. South and Central Asia is split roughly equally along earwax type.
The researchers pinpointed the gene as the ATP-binding cassette C11 gene. The researchers found that the dry type results from deactivation of the gene due to a single nucleotide polymorphism (SNP), a single change in the DNA sequence where a guanine (G) is replaced with an adenine (A). People who inherit the allele that has an A from both parents have dry earwax. Those who carry two of the alleles with G, or one G and one A, have wet earwax, making it the dominant form.
The researchers hypothesize that the original form was the wet type with the dry type originating somewhere in northern Asia. The dry form is quite common in Native Americans, providing a strong genetic link to the theory that their ancestors migrated across the Bering strait from Siberia 15,000 years ago.
Dr. Dr Sally Dawson, a lecturer in molecular audiology at University College London, UK, told the BBC News website: “This research has shown that this genetic analysis offers a method of studying how different populations moved around - such as how people may have arrived in North America.”
Journal of Young
Investigators. 2008. Volume 14.
Copyright © 2008 by Wilf Nabil and and JYI. All rights reserved.
Copyright © 2008 by Wilf Nabil and and JYI. All rights reserved.