From the Research
The PTC test is a genetic taste test that determines a person's ability to taste phenylthiocarbamide (PTC), a bitter compound, with the most recent study 1 suggesting that the ability to recognize PTC is related to blood group B phenotype, females, and risk of developing food allergy. The PTC test involves placing a small strip of paper containing PTC on the tongue to see if the person can detect its bitter taste.
- About 75% of people are "tasters" who experience PTC as bitter, while 25% are "non-tasters" who taste nothing or very little.
- This variation is determined by a specific gene called TAS2R38, which codes for taste receptors on the tongue, as supported by the study 2. The PTC test is commonly used in genetics education to demonstrate Mendelian inheritance patterns, as the ability to taste PTC is inherited as a dominant trait.
- The test is also used in anthropological studies to examine taste perception differences across populations, with a study 3 finding that balancing natural selection has acted to maintain "taster" and "nontaster" alleles at the PTC locus in humans. PTC itself is harmless in the small amounts used for testing, though it's related to compounds found in cruciferous vegetables like broccoli and cabbage, which may explain why some people find these vegetables particularly bitter, as noted in the study 4.
- Additionally, a study 5 found that a higher proportion of non-tasters were found in patients with Parkinson's disease relative to healthy comparison subjects, suggesting a possible link between PTC perception and the disease.