This article is reposted from the old WordPress incarnation of Not Exactly Rocket Science.
Fizzy drinks like Perrier and Coca-Cola are targeted at a huge range of social groups, but if fruit flies had any capital to spend, they’d be at the top of the list. Unlike posh diners or hyperactive kids, flies have taste sensors that are specially tuned to the flavour of carbonated water.
Humans can pick up five basic tastes – sweet, salty, sour, bitter and umami (savoury). But other animals, with very different diets, can probably expand on this set. And what better place to start looking for these unusual senses than the fruit fly Drosophila, a firm favourite of geneticists worldwide, and an animal with very different taste in food to our own.
Drosophila‘s tongue contains structures that are the equivalent of our own taste buds. They are loaded with taste-sensitive neurons and the activity of specific genes gives these neurons the ability to recognise different tastes.
Other researchers have already isolated the genes that allow Drosophila to tell sweet from bitter. But when Walter Fischler found a group of taste cells that didn’t have either of these genes and connected to a different part of the fly’s brain, he knew he was on to something new.
Pregnant women are generally advised to avoid drinking alcohol and for good reason – exposing an unborn baby to alcohol can lead to a range of physical and mental problems from hyperactivity and learning problems to stunted growth, abnormal development of the head, and mental retardation.
But alcohol also has much subtler effects on a foetus. Some scientists have suggested that people who get their first taste of alcohol through their mother’s placenta are more likely to develop a taste for it in later life. This sleeper effect is a long-lasting one – exposure to alcohol in the womb has been linked to a higher risk of alcohol abuse at the much later age of 21. In this way, mums could be inadvertently passing down a liking for booze to their children as a pre-birthday present.
Now, Steven Youngentob from SUNY Upstate Medical University and Jon Glendinning from Columbia University have found out why this happens. By looking at boozing rats, they have found that those first foetal sips of alcohol make the demon drink both taste and smell better.
The duo raised several pregnant rats on diets of either chow, liquids or liquids that had been spiked with alcohol. The third group eventually had a blood alcohol concentration of about 0.15%, a level that would cause a typical human to slur, stagger or become moody.
When the females eventually gave birth, month-old pups born to boozy mothers were more likely to lick an alcohol-coated feeding tube than those whose mothers were tee-total. These rats had been born with more of a taste for booze.