Make a table like the one below to record what you taste for each test round.

Share your results with those around you. 

Expand this section to see the compound on each test strip for each participant.

Taste test strips exhibit a taste due to a dominant allele on chromosome number seven. The ability to taste the compounds on the Phenylthiourea (also known as PTC) paper strip is present in about 70% of the U.S. population. The ability to taste is due to two different sets of alleles. Receptors on the tongue allow you to taste five major flavors – savory, sour, sweet, salty and bitter. Thus, their presence is a result of natural selection both for the plants which produce them and the animal which benefits from the ability to sense them. It is a benefit to be able to detect them and avoid bitter tasting foods, some of which might be harmful if swallowed. Hence, it is a trait selected for in populations evolving in an area which had/has such plants.

Phenylthiourea (also known as PTC) can be tasted by approximately 70% of the U.S. population. It is also tied to the TAS2R38 gene, a member of the bitter taste receptor family. Sodium Benzoate is often used as a preservative in foods and beverages such 1 as pickles, fruit juices, and sodas. The Sodium Benzoate strips will either be tasteless, sweet, salty, or even bitter, depending on the individual. If you are not a taster for Sodium Benzoate you will not taste anything. The ability to taste Thiourea is genetically linked to PTC because they’re similar chemicals, however, this doesn’t mean you will have the same reaction to both. PTC and Thiourea are not identical, so some people may taste PTC but not Thiourea, or vice versa. The control paper is untreated paper with no chemical and is used as a placebo to control the experiment.

Approximately 25% of the American population can taste the compounds on all three strips and nothing on the control. Within this 25%, supertasters have different levels of sensitivity. If a person can test the substance is determined by their phenotype, which is determined by the genetic genotype. We will denote supertasters with “T” and the recessive non-supertaster gene with “t”. This enables us to make this classification hierarchy: This kit is designed to determine supertaster status utilizing a control placebo paper to reduce and control for error, increasing the validity of the experiment. The control paper is not treated with chemicals, and therefore can be used to give tasters a baseline for what “no taste” would be.

Learn about DNA, chromosomes, and the role of genetics. 

Are You A Supertaster?