Boyanese (Baweanese) in Singapore

Here's an interesting aside following from our previous discussions on ear wax and ethnicities.

A casual discussion with a Boyanese lady revealed that she had wet ear wax. Just an interesting association despite n= 1.

The other interesting nugget of information was that apparently the Boyanese do not classify themselves as Malays on their NRIC (National Registration Identify Card). They are either listed as 'Boyanese' or 'Others'. This is of interest because when we are collecting ethnicity/race information for purposes of medical case studies etc, any 'Malay' data may be under-represented.

The Boyanese originate from a small island off the north coast of East Java. It is of interest to us because many Singaporean Malays trace their heritage back to the original Boyanese settlers. Ethnically they are austronesians like the other Malays. If hospital records use NRIC classifications for ethnicity, and if the Boyanese do not classify themselves on the NRIC as Malays, it may be expected the the Malay data from hospital records will not be very representative.

The Great Ear Wax Poll outcome

We don't know the ethnicity of the pollsters (n=47), nor their country of origin, but with the eye of faith, the outcome shows a nice histogram that is consistent with the Hardy-Weinberg Equilibrium (A=0.73, a=0.27). This is assuming the the three categories represents the three genotypes. This assumption may not be true. Nevertheless the outcome is interesting.

ABCC11 Transporter

The ABCC11 gene encodes for a little known member of the ABC (ATP binding cassette) superfamily of membrane transporters. The protein is called MRP8 or multi-drug resistance protein 8. Not much is yet known about its function. It became 'famous' largely because of its association with the dry-wet ear wax phenotype. Additionally, it has been shown to transport cyclic nucleotides e.g. cAMP and cGMP, and consequently has been implicated in resistance to a number of nucleotidic anticancer drugs used for breast cancers.

Other interesting associations other than ear wax....is the association with the production of colustrum by nursing mothers (early milk).

The main genetic polymorphism associated with ABCC11 is the 538G-A transition in exon 4 giving rise to a substitution of glycine to arginine. The frequency of this polymorphism is unknown among our local ethnic groups is Singapore.

What's with the Japanese - wet or dry ear wax??

Another interesting bit of trivia I discovered when I visited RIKEN. There is a genetic polymorphism affecting the ABC (ATP-Binding Cassette) transporter ABC11, that determines if your ear wax comes out dry or wet. This was discovered by Yoshiura et al in 2006. See also report in the New York Times. Apparently the Japanese and Koreans (and Northern Chinese) exclusively have the 'dry ear wax' variant while African and West Europeans have the "wet ear wax" phenotype. The rest of the world have mixed proportions of dry and wet waxes. In Southern China and South East Asia, the frequency of wet wax increases. It is thought that the dry wax allele originated in Northern Asia, thus giving rise to an exclusive distribution of the allele in North China, Korea and Japan.

Wet is black, dry is white

The Japanese use the dry wax phenotype to distinguish the Yamato Japanese from the other Japanese arising from Hokkaido (Ainus) and Ryukyu (Okinawans).

Why not take the ear wax poll?