Evidence of the genetic basis that determines whether human earwax (cerumen) is wet or dry, is published in the March issue of Nature Genetics. Dry earwax is found frequently amongst East Asians, while wet earwax is frequent amongst individuals with African and European ancestry.
Ko-ichiro Yoshiura and colleagues studied the gene association with earwax type by examining Japanese individuals with either type of earwax. Their results identified the gene ABCC11which encodes for a cell channel. This channel controls the flow of molecules which directly alter earwax type. Any mutation in the gene can change the structure of the channel, reducing its activity and subsequently affecting the type of earwax produced.
The authors compared this gene in individuals in 33 populations world-wide. They suggest a change in the channel to have first occurred in North-East Asia which has subsequently spread throughout Asia, as well as to populations such as the Native Americans and Inuit with origins in Asia. This study provides an interesting example of understanding the genetic basis of normal human variation, not directly linked to a disease phenotype.
Koh-ichiro Yoshiura (Nagasaki University Graduate School of Biomedical Sciences, Nagasaki Japan)
(C) Nature Genetics press release.
Abstract available online.
Message posted by: Trevor M. D'Souza