In recent posts, I have written about the environmental factors that influence how we perceive food and drink. To complete this mini-strand, I offer a few words on the genetics of taste perception.
Back in 1931, a chemist called Arthur Fox was carelessly working
with a powder called phenylthiocarbamide (TCP). His colleague complained that
some of the airborne powder tasted bitter, but Fox could not taste anything.
Studies to date have confirmed that around 75% of people can taste TCP and 25%
cannot. With increasing knowledge of genetics, this ratio strongly suggested that a
single dominant gene was involved in TCP perception; though the fact that
people vary in their sensitivity to it suggests that other factors are also
involved. In 2003, geneticists identified the gene – TAS2R38 – coding for the TCP
TCP does not occur naturally, so what is the significance of
this? The answer was once life or death, of course. The TCP receptors are just
part of the structures on the tongue that detect bitter substances. There are
now around 30 genes linked to such bitter taste receptors. Your ability to
taste TCP is positively correlated with your ability to taste other bitter
substances, most significantly toxic compounds in plants that you might want to
I was reminded of this at Green Man this summer. One of the
University Science Department stands in the Einstein’s Garden area of the
festival was conducting simple genetic test, including the one for TCP
perception. As on previous occasions,
this confirmed that I can taste TCP. Though this leaves a bitter taste in the
mouth, it is a good thing (and they did supply sweets afterwards). It means I
have a better chance of detecting bitter toxins in my food than people who
cannot taste it, or it would if we all still lived in the age before
The genetic component for the perception of the other four
basic tastes is thought to be less strong, though recent research has revealed
that the perception of sweetness is partly inherited. This research is being
done with a view to understanding obesity. Genetics may have little bearing on
how we perceive salty and sour, while less is known about unami generally.
There are a number of technical terms to describe
medically-related conditions involving taste perception, but these are more
linked to environmental factors, particularly the onset of certain diseases,
than genetic factors. For example, people can have ageusia (complete loss of
taste), hypogeusia (partial loss of taste), dysgeusia (distorted sense of taste)
and hypergeusia (abnormally heightened sense of taste). While ill, I have
experienced mild versions of a couple of these and it certainly makes you appreciate
your food when you recover.
One of the many environmental factors influencing how we
perceive taste is aging, with older people often having reduced sensitivity to salty or
bitter tastes. Acquired tastes are preferences that develop over time.
These can override any genetically determined aversion to bitter or unusual tastes.
Coffee, Marmite, broccoli, goat’s cheese and Brains Bitter, for example, are acquired
tastes. It all goes to show that taste can be a very personal thing.
Crossmodal sensory perception
Pete Brown on beer and music
Some archived posts you may be interested in:
Genetics at the National Botanic Gardens of Wales
Raw Vegan Rock and Roll