genetics of bitter taste

My husband has always hated raw broccoli, Brussel sprouts, and coffee.  Turns out he is not just being picky, he can actually taste a bitter flavor that I can’t detect.  It really is all in the genes!

It was discovered in the 1930’s that some people can taste a bitter compound known as phenylthiocarbamide (PTC) while to others it has no bitter taste.  You may remember this as a classic biology class activity about inheritance involving PTC taste paper.  PTC is a similar compound to one found in foods such as broccoli, cabbage, Brussel sprouts, coffee, and dark beer, which can taste bitter to some people.  The snp rs713598 on the gene TAS2R38 is a mostly accurate predictor of whether a person is a taster of PTC or not.

Another bitter compound is known as PROP or 6-n-propylthiouracil.  A group of three snps on the TAS2R38 gene will give the range of whether a person is a ‘taster’ or not.

From a study on nutrition and taste:

For example, the TAS2R38 gene is characterized by three non synonymous coding SNPs (rs713598 – G145C, Ala49Pro; rs1726866 – T785C, Val262Ala; rs10246939 – A886G, Ile296Val) which give rise to several haplotypes… Subjects possessing at least one copy of the PAV haplotype (i.e. the alleles coding for proline at rs713598, alanine at rs1726866 and valine at rs10246939) are significantly more responsive to the bitter tastants PROP, PTC, and chemically similar compounds… Such individuals display the so-called taster phenotype, and are distinct from those who are homozygous for the AVI haplotype and display the so-called non-taster phenotype. Tasters show a reduction in their intake of several vegetables such as cabbage, spinach, lettuce… Given the importance of diet in longevity, genetic variation in taste receptor could directly affect a healthy aging by modulating food preference during life.

To figure out your taster genes, check your 23andMe results for the following snps:

Check your 23andMe results for rs713598:

  • At least one G — can taste bitter compounds

Check your 23andMe results for rs1726866:

  • At least one G — can taste bitter compounds

Check your 23andMe results for rs10246939:

  • At least one C — can taste bitter compounds

Everyone is different, and the SNPs above are accurate for about 80% of people.

Note on SNPedia orientation information on rs713598:

Each rs# in SNPedia has a field along the right side called ‘Orientation.

If the value is ‘plus’ you don’t need to do anything, 23andMe agrees with dbSNP.

If the value is ‘minus’ you need to change:

A->T
T->A
C->G
G->C

 Links:

Categories: Genetics

5 Comments

Tom · March 13, 2015 at 11:42 am

Are you sure this is correct? According to 23andMe, I have the genotype CC, but I’m definitely a taster. I’ve also always hated broccoli, Brussel sprouts, coffee and dark beer. I force myself to eat broccoli since it’s so healthy, but have never drank coffee apart from the occasional sip. Won’t even eat tiramisu. When I was a teenager and started to drink beer I even detested lager beer and found the taste too offputting, but drank it anyway (peer pressure I guess). According to the SNPPedia article you reference, it is GG which is unable to taste bitter, but those letters never seem to match up with what is displayed in 23andMe’s raw data.

    genelife · March 14, 2015 at 1:09 pm

    Thanks so much for your comment on this! I’m going to look into this more and update the post. You are right that the snpedia entry shows that GG is unable to taste bitter, but the 23andMe health trait report has it the opposite way with CC being unable to taste bitter. (https://www.23andme.com/you/journal/bittertaste/overview/) I’ll try to find out which one is correct!

      genelife · March 15, 2015 at 1:26 pm

      Just wanted to follow up to say that the SNPedia article is showing the opposite orientation for the SNP than what 23andMe shows. Usually that is an easy thing to spot, but for this SNP it is confusing with both alleles being C and G. I added in a little more information to the post to hopefully make it clearer to everyone. Again, thanks for your comment!

Danielle · October 26, 2015 at 9:20 pm

I’m CC too and I can taste bitter. AA and TT for the other 2 snps you mentioned. I have more of a tolerance for it now that I’m older but I still am not a big fan of bitter foods.

Sunshine · September 21, 2018 at 3:47 pm

I have all the markers for tasting bitter, and I feel like I can taste bitter flavors very well. But I love them! Love bitter IPAs, black coffee, crucifers of all sorts.

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