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Breaking Science

The Breaking Science team come to BBC Radio Five Live to break open this week's science stories.

The Breaking Science team discussed new research that might help our understanding of how we smell:

Kat Arney: They do say a rose by any other name would smell as sweet, but what does make us think that a rose smells nice but my feet smell bad? My feet don’t smell that bad. But until now scientists have known relatively little about how the smelly molecules, known as odorant molecules, are recognised by the receptors in our noses. But new research by Harumi Saito published in the journal Science Signalling this week could shed some light on this mystery.

Chris Smith: So come on then, tell us why does a rose to me smell like a rose and your feet smell, well let’s not go there.

Kat Arney: Well our sense of smell is an amazing thing and our noses have hundreds of olfactory receptors, each of which can pick up a different smelly molecule and this then sends a signal into the brain which gets interpreted as a smell. But we only know around about 50 of these smelly molecules and that somewhat limits our understanding of the whole system.

Chris Smith: So what are the researchers actually doing in this study to try and home in on what’s going on?

Kat Arney: Well they used a technique called high throughput screening which allowed them to carry out many, many experiments in a short time, and this allowed them to test 93 different odorants, these are the smelly molecules, against a panel of 464 different olfactory receptors, and they picked up 52 specific odorants that activate mouse receptors and the screen pulled out 10 new odorants that activate human receptors.

Smelling a flower.
[image © copyright Jupiterimages]

So this has, you know, made a big increase on what we know about the number of specific molecules that interact with the smell receptors. And the scientists used the knowledge from their screen to then develop a computer model that can help to predict what kind of odorant molecules might fit with different olfactory receptors.

Now it’s probably possible to look at a whole range of smelly chemicals and try and predict which olfactory receptors they might bind to. So this is basically going to speed up the process of research in this area so scientists will have better ideas of which routes to follow rather than just taking shots in the dark.

Chris Smith: It’s interesting because before Christmas I spoke with a perfumer who makes smells for a living, nice smells, and he had the chemical equivalent of synaesthesia, he could imagine a smell and see the molecule in his mind’s eye that would smell like that, so I guess he’d be very interested in a function or a model like that.

Kat Arney: Absolutely. Fascinating.

Listen to the whole programme, originally broadcast on BBC Radio Five Live, February 2009

Blogging about

Breaking Science

The Breaking Science team come to BBC Radio Five Live to break open this week's science stories.

The Breaking Science team discussed the latest thinking about an unusual condition

Chris Smith: Talking about genes and how they’re linked to different conditions, there’s one very exciting condition which I’ve always wished I had just to be able to experience it, and that’s synaesthesia - the mixing of the senses - and scientists now reckon they’ve got one of the genes for that.

Kat Arney: Yes. Synaesthesia is a really fascinating neurological condition and it manifests itself in a range of ways. And it’s reasonably rare, it affects fewer than one in a hundred people, and it’s really described as if the sensory wires were crossed in your brain.

So for example, people with synaesthesia can smell colours or taste sounds, and now researchers in London, Cambridge and Oxford have tracked down specific regions of the genome that harbour genes that are linked to audiovisual synaesthesia. And we do know from previous research that this condition can run in families, but researchers haven’t been able to pinpoint the genes that might be involved. But now writing in the American Journal of Human Genetics, Dr Julian Asher and his team used new genome scanning technology to hunt for genes that were linked to synaesthesia, and they used 43 families that had this condition in the family.

Tasting the colours? A woman with a lollipop.

[image © copyright Jupiterimages]

Chris Smith: And what have they found in those families?

Kat Arney: So far they’ve found four regions of the genome that are linked to synaesthesia. These were on human chromosomes 2, 5, 6 and 12. Now they haven’t found specific genes, they’ve just tracked down some general regions, and the regional chromosome 2 is probably the most intriguing, as it’s also been linked to autism and people with autism often have differences in their perception and their senses.

Chris Smith: But in what they did find, was there anything of interest in there?

Kat Arney: Well of the regions that they did find there are some very interesting genes in there, such as genes for epilepsy, genes that have been linked to dyslexia, learning and memory in some of these regions which obviously need a lot more investigation. And so far, although they haven’t found any specific genes, there’s a lot of candidates which we could look at in future.

Chris Smith: As they say, nature normally reveals her workings through her mistakes because it gives us an insight into the molecular clockwork of how things like the brain actually work.

Kat Arney: Absolutely.

Episode originally broadcast February 2009 on BBC Radio Five Live. Listen to the full programme online.

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