About this experiment
A Question of Taste explores the evolution of an unusual trait in humans, where some people taste a particular chemical as being horribly bitter, while others can't taste it. Why have we evolved these two different responses? What advantage could each have given us?
There are two parts to A Question of Taste:
- a chance to find out whether you're a 'taster' or not, plus take part in a UK-wide survey
- day-long workshops taking place at locations across the country, where PCR techniques will be used to explore the genetics behind the ability to taste
Why are some people tasters?
The chemical involved in this is called phenylthiocarbamide, or PTC for short. To people who can taste it, PTC is very bitter. For others, they cannot taste anything at all.
The TAS2R38 gene encodes a taste receptor, which is found on the tongue. Differences in this gene affect whether people can taste PTC. These differences in genetic make-up can be described as genotypes. The ability to taste or not taste PTC is described as a phenotype, an observable effect of the genotype.
Recent research has shown that Neanderthals also had this genetic variation. 48,000 year-old bones have been analysed and found to contain both the taster an no-taster gene, so the debate over whether sprouts are food heaven or food hell has already been raging for at least half a million years.
Are you a taster?
In your X-Bacteria kit you'll find PTC-impregnated paper strips. Suck on one of these and you'll soon find out whether you're a PTC-taster. Use these strips with your students to find out if they are tasters or not. Instructions for carrying out the experiment are included in the kit, and can also be found online in Resources. You can then log your class results into our Survey and view Results from across the UK.
As well as this experiment, there are also A Question of Taste Workshops being run across the UK. These workshops were developed by the three science centres:
The Association for Science and Discovery Centres are co-ordinating the delivery of these workshops across the UK. These workshops allow post-16 students to use molecular biology techniques such as PCR and gel electrophoresis to investigate their genotype at the TAS2R38 gene. They will also compare the same characteristics in humans and chimpanzees, and discuss convergent evolution.