Koh-ichiro Yoshiura,
Akira Kinoshita,
Takafumi Ishida,
Aya Ninokata,
Toshihisa Ishikawa,
Tadashi Kaname,
Makoto Bannai,
Katsushi Tokunaga,
Shunro Sonoda,
Ryoichi Komaki, [......],
Mihoko Kikuchi,
Graciela Russomando,
Kenji Hirayama, Minaka Ishibashi,
Aya Takahashi,
Naruya Saitou,
Jeffery C Murray,
Susumu Saito,
Yusuke Nakamura,
Norio Niikawa
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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.
Nature Genetics 03/2006; 38(3):324-30. · 35.53 Impact Factor
