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A SNP in the ABCC11 gene is the determinant of human earwax type
Journal article   Peer reviewed

A SNP in the ABCC11 gene is the determinant of human earwax type

Aya Ninokata, Graciela Russomando, Koh-ichiro Yoshiura, Christophe K Mapendano, Norio Niikawa, Susumu Saito, Akira Kaneko, Naruya Saitou, Vladimir A Saenko, Makoto Bannai, …
Nature genetics, Vol.38(3), pp.324-330
03/2006
DOI: 10.1038/ng1733
PMID: 16444273

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Abstract

Human earwax consists of wet and dry types. Dry earwax is frequent in East Asians, whereas wet earwax is common in other populations. Here we show that a SNP, 538G → A (rs17822931), in the ABCC11 gene is responsible for determination of earwax type. The AA genotype corresponds to dry earwax, and GA and GG to wet type. A 27-bp deletion in ABCC11 exon 29 was also found in a few individuals of Asian ancestry. A functional assay demonstrated that cells with allele A show a lower excretory activity for cGMP than those with allele G. The allele A frequency shows a north-south and east-west downward geographical gradient; worldwide, it is highest in Chinese and Koreans, and a common dry-type haplotype is retained among various ethnic populations. These suggest that the allele A arose in northeast Asia and thereafter spread through the world. The 538G → A SNP is the first example of DNA polymorphism determining a visible genetic trait.

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