Blinding Insects To Smells May Be The Best Repellent

Scientists have unearthed a genetic linch pin which enables insects to pick up smells. Without it they cannot detect airbourne odours, including their next meal, a finding which researchers hope will lead to the development of powerful new insect repellants capable of making humans and crops invisible to mosquitoes and pests. Leslie Vosshall and colleagues, from Rockefeller University, found that insects including disease-spreading mosquitoes, plant pests like the corn earworm moth (which damages corn, tomato and cotton), and fruit flies which home in on rotting fruit, all rely on the same gene - dubbed Or83b - to detect smells. When the researchers removed the gene from laboratory fruit flies, the insects essentially lost their sense of smell. To find out why the team looked more closely at the insects' antennae - their equivalent of a nose - and found that all of the receptors that enable nerve cells to pick up the presence of an odour were missing. But they came back when the scientists replaced the absent Or83b gene, even if it was the equivalent gene taken from an insect of a different species. The Or83b gene therefore seems to play a key role in ensuring that smell receptors find their way to the correct places on the nerve cells in insect antennae and might prove to be an Achilles heel which can be exploited for the development of novel insect repellents which work by blocking insects' senses of smell. According to Leslie Vosshall, "If we could use this to interrupt the transport of odourant receptors, we could make mosquitoes 'blind' to humans. That in turn would be a good way to prevent disease transmission". The researchers are therefore hoping that it will be possible to develop novel insect repellents which work by blocking the action of the gene.

20th Mar 2005

Science in a Cup of Tea

BROWNIAN MOTION - Philippa Law interviews Dr Lucy Green & Greg Foot

Philippa - This week, I've been finding out how you can see Einstein's science in a cup of tea. Here's Dr Lucy Green from Cardiff University with a quick cookery lesson.

Lucy - The first thing you do would be to fill up your kettle using cold water from the tap. The water is at a low temperature, and the molecules are moving around in your water but they're not moving terribly fast. When you heat it, what you're doing is giving energy to particles in the water. The water molecules then start to move much much faster.

Greg - These particles are far too small for us to see. They actually all travel in straight lines until they hit another one, bounce off, and carry on in a different straight line.

Lucy - When the water boils, you pour the water into your pot of tea with your tea leaves and then give it a stir. Even once the water has settled down, you can still see the tea leaves being jostled around within the water. And that's because the molecules have energy and they're bumping into the tea leaves and making them move.

Greg - Each time a water molecule bangs into a tea leaf, the leaf's going to move slightly in a different direction. This means that you can never predict the way in which it's going to move. Although your cup of tea looks completely still, underneath the surface it's made of all these particles moving rapidly and randomly in all directions.

Lucy - That's something we call Brownian motion.

Philippa - Why's it called Brownian motion?

Greg - Everyone says 'Einstein - Brownian motion'. But Brownian motion was actually discovered by this guy Robert Brown in 1827. That's why we call it Brownian motion. This guy was looking down his microscope at pollen particles in water and saw that they jiggled around a bit. He thought that this meant they were alive. Then what he did was to try some really old pollen and found that it did exactly the same thing. This showed him that it wasn't anything to do with the pollen particles being alive. But no-one could actually explain what caused it until Albert Einstein came along. Einstein said that if atomic theory was right, then using his explanation, it would explain why the pollen particles moved in these jiggly patterns.

Lucy - Einstein really gave us an understanding about what the water is made of. Before Einstein started working, so about 100 years ago, no - one knew that molecules or atoms actually existed, so they didn't know fundamentally what the water was made of.

Philippa - Einstein said that water was made of atoms, but wasn't it Einstein's atomic 'theory'? Doesn't the word theory mean that it hasn't been proven? Does that mean that atoms might not exist?

Lucy - Well we can actually use special instruments now that can see down onto the scale of atoms. Even thought we can see them today, 100 years ago when Einstein was thinking about this problem, he had no way of being able to see an atom because they are so small. So he just had to do a thought experiment. Einstein thought about what he had seen with the tea leaves being bustled around, and he came to the conclusion, which is actually the most logical conclusion, that water is made of molecules that are too small to be seen and that the molecules bump into the tea leaves and make them move.

Philippa - What other kind of things are impacted by Einstein's work with tea?

Lucy - Lots of things! Even in medicine the whole idea of the existence of the atom is used every single day. For example, if you have to go and have a scan made of the inside of your body, the methods that are used involve using atoms. In fact, using atoms that decay and split up because they are so large, you can have small amounts of these atoms injected into your body. Say for example you wanted to study the brain. The brain uses glucose to be able to work. So these atoms will travel up your blood vessels and into your brain. They'll then localize themselves in the area where glucose is being used. So Einstein's work on a cup of tea also helps us understand hw the brain works.

Philippa - Do you reckon Einstein was good at making tea?

Lucy - I think he must have been amazing at making tea! I think he probably had a very logical process and made in hardly any time at all!

March 2005

The Cambridge Science Festival

Chris - Were now going to go over to the Cambridge Science Festival where we were yesterday. The Cambridge Science Festival attracts around forty thousand people and is the biggest free festival in the whole country. The idea is to build confidence in what scientists are doing and to show the public how exciting science can be. We went to find out what was going on at Science on Saturday. We discovered how bees pollinate flowers, how to dissect a sheep's eyeball and also why boats mysteriously disappear in the Bermuda Triangle. Here's what we found.

Carolyn - We're filling film canisters with lemon juice and baking soda and they should go boom any second now…

Sarah - So Carolyn, what's the science behind the experiment you're doing here today?

Carolyn - We're looking at the reaction between an acid and a bicarbonate. What it's producing is carbon dioxide, which is the gas we see in the bubbles. The kids get to see the concept that gases take up more space than a liquid or a solid. We often try to show them with the top off so they can see the gas being produced and thus what creates the explosion.

Sarah - So the acid is reacting with the bicarbonate to produce carbon dioxide. How much lemon juice and bicarbonate should the children mix in their film canister at home?

Carolyn - We're doing about a quarter to half a teaspoon of each. You have to stand back so you don't get it in your eyes!

Chris - That was Naked Scientist Sarah Smith finding out why lemon juice and bicarbonate of soda goes bang. Now Brian Wallace caught up with Cambridge University's Rik Jenkinson who was doing a funky demonstration to try to explain why boats disappear in the Bermuda Triangle. Here's what he found out.

Rik - The reason why things float is because there's more pressure underneath them than the gravity pulling them down. If you create less pressure underneath something, the thing will sink. This is what we believe to be happening in the Bermuda Triangle. A bubble of methane or some other gas wells up underneath the ship creating less pressure, meaning that the ship sinks.

Brian - Could you talk us through this experiment while you do it?

Rik - Ok, we have our ship floating on our miniature Atlantic Ocean, which is in fact a fish tank. What we're going to do is create our upwelling of gas underneath, which will male the ship sink. Now we do this using a converted vacuum cleaner. Now if we just switch that on…. Now what's happening is that we're creating a load of bubbles underneath the ship, which means that there's less pressure supporting the ship on the top of the water. Eventually, yep there it goes, the ship will sink beneath the surface. Now if we switch the hoover off, the ship remains at the bottom because it's full of water.

Chris - That was Naked Scientist Brian Wallace talking to Rik Jenkinson explaining why ships mysteriously disappear off the Bermuda Triangle. Now to someone who's clearly enjoying themselves at the Cambridge Science Festival, Vice Chancellor Professor Alison Richard. Here's what she had to say about the festival.

Alison - Cambridge University is about research but also all about education. We educate our students to be sure, but we have a responsibility and a passion to reach out to the next generation and the community around us. As you've seen, there are children here today of every age, including a few 80 year old children! Even very small kids are here being fired up and their energies being set alight.

Chris - One criticism of this type of thing from some angles is that it often ends up preaching to the converted - preaching to people like me who already love science. Do you think that's true here, or do you think you're getting an additional audience that wouldn't normally be exposed to science?

Alison - I would guess just by looking around and listening to people here that people are looking for something to do with their children on a Saturday morning, and I'm not at all persuaded that this is forty thousand scientists here this week. These are people with an interest in the world and we're going to capture their interest in science and show them the wonders of science.

Chris - It's quite an adventurous thing to do to fling wide the gates of Cambridge University and invite the public in and say come and have a look at what we do.

Alison - I suppose it's adventurous (loud bang in background) woah, my goodness! Well that was adventurous! I think that it's great thing that we do and we do it in various ways, and the Science Festival is one of the flagship ways we do it. As you know, this is the twelfth year we've been doing it, and it's going from strength to strength. I hope that we can carry out the science festival to other parts of the region from time to time so it doesn't always bring in people from Cambridge, but so we can take Cambridge to the region.

Chris - Now what's this pink sausage you have here?

Alison - I'm very proud of my pink sausage! This is a Salmonella enterica with its flagellae. I blew it up myself and tied it off and I'm going to take it home and give it to my children. Now they are 22 and 24 years old but I know that they will be very proud of their mother for having made this bacterium.

Chris - I suppose we ought to say that when you blew it up, it's a balloon isn't it.

Alison - Yes, it's a pink balloon.

Chris - So what's been your favourite experiment you've seen here today?

Alison - Well I really like my balloon, I have to say! But I was also just watching an experiment showing how earthquakes happen and how buildings fall down under the influence of different levels of oscillation. It was wonderfully simple but really graphic. I and a little boy of about six both stood there completely riveted being taught by a Cambridge undergraduate. And I just thought that this is really really great. It's all generations, it's teachers and students of all ages. This is what this festival is about.

Chris - Cambridge Vice Chancellor Professor Alison Richard, who was enjoying the Science Festival and explaining why she thinks it's so important. If you wondered what that huge bang was in the middle, that was Dave Ansell and his team who were electrolysing water - splitting water up to make hydrogen and oxygen - and then lighting it to make it go bang. Unfortunately, their experiment worked a bit too well and it blew the apparatus to smithereens, which is what you heard in the middle of her interview! Now let's find out what Rosie, who's twelve years old and lives in Trumpington in Cambridge, had to say about the festival. She found the experience incredibly informative and it triggered her desire to study science and perhaps go on to become a vet.

Chris - You've just chopped up a sheep's eyeball. That's not something you presumably do every week.

Rosie - No it's not. I've never done it before and it was really great to do it today.

Chris - You weren't grossed out at all?

Rosie - I was a bit at the beginning because of all the goo. When you put the knife in, all the goo just came out. That was a bit disgusting, but the rest of it was ok once you got over that.

Chris - Has it helped you to understand a bit more about how eyeballs worked though?

Rosie - Yeah it's been great. I know how it works and how the light gets in and how they can see in the dark and all about the pupil. Just loads of stuff about sheep's eyes.

Chris - If you'd read that in a book do you think you'd understand it as well as now you've done it for real?

Rosie - No, when you read it in a book you don't really know what really happens. It's a lot more effective when you do it and actually take it in.

Chris - what else have you seen at the Science festival today?

Rosie - We went to the Museum of Archeology and Anthropology and we did stencils of our hands on the wall like they did millions of years ago. And we saw how the continents have moved. They used to be really close together and now they've expanded out. That's as far as we've got, but we're going to do a lot more I think.

Chris - Do you think you'll be a scientist when you leave school?

Rosie - I'm not sure. I like animals so I want to be a vet but I think I want to do a bit of science as well because I like science.

Chris - It's quite a hard course being a vet. Do you think you're up to it?

Rosie - I think so. I really like doing all this, so I think so.

Chris - Hopefully you won't be chopping up too many of your pets' eyeballs though because presumably you'll be making them better rather than dissecting them.

Rosie - No, I don't think I'll be doing this to live animals!

Chris - That was Rosie from Trumpington who was enjoying the delights of Science on Saturday. Anna Lacey, one of the Naked Scientists, got talking to Lynn Harrison from the Institute of Continuing Education to find out how you can make your own latest designer jewellery - a DNA necklace.

Lynn - What we're doing here today is giving everyone an opportunity to extract their own DNA, see it, and then take it home with them. And we're putting it in a little necklace that they can put round their necks and take home with them if they want to.

Anna - Exactly how does the experiment work?

Lynn - First of all they have to collect a sample of their own cells buy collecting cells from the inside of their mouths. And then we break them open with some detergent, and we use an enzyme to chop them up a bit. Then we heat it to 50 degrees and that helps the DNA to come out of the cell. Then we need to precipitate the DNA out of solution so you can actually see it. We do that by adding alcohol, as DNA isn't soluble in alcohol. The DNA then comes out of solution and you can see these long white threads and they all clump together in the test tube. We can then take the DNA and alcohol and put it into these little necklaces so they can actually have something.

Anna - What are you hoping to get out of today for the children?

Lynn - It's to make them realise how real DNA and genes and genetics really are. When people get to see their own DNA, they start to think about it in a different way. It seems much more real.

Chris - So that was Naked Scientist Anna Lacey talking with Lynn Harrison from the Institute of Continuing Education at Cambridge University to find out how DNA is more than just a picture in a textbook. In fact it's so real that you can hang your own DNA round your neck. Now we're going over to speak to Plant Sciences lecturer Keith Johnston about the buzz behind pollination.

Keith - What you can see here is an interactive exhibit for young children to learn about pollination. The aim is that they dress up in a bee outfit to look like bees and they have little dangly bits they put on their heads. They can then dive into this great big plant we've generated and as they do that they pick up pollen which sprinkles out from little containers on top of the plant and spreads over them. They then get into the centre and find the nectar, which is of course a sweet. And so they come out of the plant having got hold of their sweets.

Anna - OK, and this young man here looks like he's already been in the flower. How was it?

Niko - Cool. Yeah, well I nearly didn't fit, but it's nice.

Anna - The Haribo were worth it.

Chris - Twelve year old Niko there munching away on his Haribo nectar, and Keith Johnston explaining how the science of the festival is helping to teach young children about pollination.

March 2005

Left-handedness

Professor Chris McManus, University College London

Chris - Now Chris, you wrote a book, 'Right Hand, Left Hand', which won you a whole heap of prizes because it's something people are absolutely fascinated by. Why do these left-handers exist?

Chris M - The simple answer is because of genes. Some of us have one set of genes while others of us have another. It's the same reason that some people have blue eyes or blond hair. And therefore, some people just have their brains the other way round. That's the simple answer. The really difficult question to answer is why did that ever happen? Why did we become mostly right handed in the first place and why did others become left handed? That's a good evolutionary story as there have to be advantages to being right handed and advantages to being left handed. They're difficult questions.

Chris - Lots of people say that sportspeople are better if they are left handed. Is that true?

Chris M - It's true for some sports. It's not true for playing golf for instance. It doesn't mater which hand you use to hit a tiny ball into a hole that's very far away. You're equally good if you're right or left handed. However, left handed tennis players have a strategic advantage. The reason is is that right handers aren't as used to playing left handers as left handers are to playing right handers, and therefore the left handers benefit from it.

Chris - If we were to look back in the past, how do we know if left handedness was equally common then as it is now?

Chris M - It's quite difficult, but behaviour does get recorded. If you look at old paintings or old sculptures, then there's good evidence that about 90% of people were left handed back until about 5000 years ago when people started making paintings. Before that it gets more difficult. We can look at the iceman found up in a glacier in the Alps a few years ago. He died about eight or ten thousand years ago. He was carrying arrows, and you can tell by the way those arrows were wound and the way the feathers were put on that two had been wound by right handers and one had been wound by a left hander. So you can use all sorts of tricks like that. You can look at stone tools which are two million years old, and interestingly when you pick up a stone and hit it with another one, a right hander does it differently to a left hander.

Chris - Were around 10% of cavemen left handed and 90% right handed then?

Chris M - We think so 200 000 years ago but we're not sure two million years ago. That's the big question.

Chris - Now during our piece on the Science Festival, young Rosie said that she'd been over to the archeology department and used a blow pipe to make an imprint of her hand on a wall. There was a wonderful experiment done by some scientists in Montpellier in France looking at this question in cave paintings. Tell us a little bit more about that.

Chris M - Essentially what you find is negative prints of hands on the wall of the cave. What they seem to have done is to fill one hand with charcoal from out of the fire, put the other hand against the wall and then blown the black powder all against the wall. They've then removed their hand and left an outline of their hand. About three quarters of these hands are left hands, and the other quarter are right hands. The really tricky question is what is the ratio of left and right handedness? Most people use their right hand to hold the dust and blow it onto their left hand. Not everybody does that. So they got modern students in Montpellier doing this, and they found that about three quarters of the time they put a left hand up; the other quarter a right hand. Since nowadays about 10% of people are left handed, we can be mostly certain that about 10% of people then were left handed.

Chris - A couple of weeks ago we published a story about work at the University of Limerick about racehorses. They found that certain horses have a preferred direction. The males seemed to prefer going left, and the females seemed to prefer going right. This was true whether they were deviating around an obstacle or rolling over. Do you think it's true that animals have a preferred hand or foot?

Chris M - There are lots of stories about this. The general story is that individual animals are generally a certain handed, footed or paw-edness, but exactly half of them are left handed and half of them are right handed. I would say that you could try this with your cat at home. Get a tin of cat food, leave about half an inch of food in the bottom and watch which paw it uses to get it out. They're pretty well consistent, but about half of them use the right and half of them use the left.

Chris - Tell us about the Muppets and about Titanic.

Chris M - The Muppet story is an interesting one. Muppets are left handed. Jim Henson who created the Muppets was left handed, and so the standard story you find on all of the websites is that this was the left handers revenge. He wanted to create a world where most people were left handed and only a few people were right handed. Needless to say, it's not true. The real story is much more interesting. It's very difficult being a puppeteer. The most difficult thing about being a puppeteer is controlling the head, because you have to get all of the movements of the head right. So puppeteers use the right hand, the most skilled hand, for moving the head. The second most difficult thing is controlling the hands, so they use their left hand to do that. So most Muppets are left handed. It was nothing to do with Jim Henson being left handed at all.

Chris - Now what about the film Titanic, because all the people in it who are waving from the docks are all waving with the wrong hand.

Chris M - What happened with the Titanic is that they didn't have enough money to build a whole boat, so they built half a boat. The problem was that they needed to see people from both sides of the boat. So they filmed them on just one side of the boat but flipped the images over in the camera. They taught all the main characters to do things with their left hand and had the insignias on hats in mirror writing, but unfortunately they couldn't train the five thousand extras on the dockside to wave with their left hand. They waved with their right hand but it looked as though they were waving with their left hand.

March 2005

Autism And Synaesthesia

Professor Simon Baron-Cohen, Director of the Autism Research Centre

Chris - What actually is autism?

Simon Baron-Cohen's book The Essential Difference, which explores the difference between male and female brains and the basis of Asperger's and autism.

Simon - Autism is a childhood condition that we now understand to be the result of brain development just not being typical, and it results in the child having social difficulties, trouble making friends, and communication problems. Some of these children are late to talk or may never develop speech, and others just can't chat. There is also another feature which is narrow interests or obsessions.

Chris - But that just goes along with being male to a certain extent doesn't it?

Simon - We do know that more boys than girls end up with a diagnosis like this but we should be careful not to say 'is this all males?' because this is a medical condition and the diagnosis is only given out if the person is suffering in some way. So just because you are having some trouble socially or because you have strong narrow interests, that doesn't necessarily interfere with your life. But if it's so severe that it's actually causing you to be depressed, be very isolated or having trouble with education, you might end up in a clinic and need a diagnosis.

Chris - If you look at brain scans of people that have autism spectrum disorders, can you see any difference between them and what's considered normal?

Simon - Yes, there are findings coming out and that's one of the exciting results of having brain scan technology like magnetic resonance imaging. The first finding is that a proportion of people with autism have larger brains, and there's a whole suggestion now that the brain may be growing too fast in the first two years of life. Another difference is that when you use functional imaging, where you can see how the brain is functioning while the person is doing a task, the usual areas that should be active in a typical brain are not necessarily active in a brain of someone with autism. There's a special part of the brain called the amygdala, some people think of it as the emotion centre, which doesn't typically get activated in the autistic brain when they're thinking about emotions or looking at people's faces. In the more typical child or adult, the amygdala is very important for recognising how somebody else is feeling.

Chris - And that could explain why people with autism classically have a problem with relating to other people.

Simon - Absolutely. We don't really understand why social interaction happens so easily. For most of us, we chat, make friends and socialise without even thinking about it. For someone with autism, that can be the hardest thing. It's as if one part of their brain that should be working, if you like, naturally on autopilot, is not working in the normal way.

Chris - Didn't you do a study at the maternity hospital showing that one day after birth, children of one sex or the other already show some differences?

Simon - Yes. We were interested in sex differences in the general population and its possible link with developing autism. We looked at babies that were just 24 hours old, and we showed them either a human face or a mechanical mobile suspended above the crib. We were interested if babies would look equally long at each type of object. Some of your listeners may guess the result. What we found was that little boys, even on the first day of life, looked longer at the mechanical mobile, and little girls looked longer at the human face. Now finding a sex difference like that at birth, effectively, suggests that biology must be contributing to what we all recognise as differences on average between males and females. It's not that culture and experience don't also play a part, but finding it at birth also makes biology an important part of the explanation.

Chris - There was an unfortunate furore created that has now become a major health problem across the whole of our region and the country, which is in relation to the MMR. This was because a certain person down in London published a paper suggesting that the MMR vaccine may be linked to autism. It's subsequently been disproved hasn't it?

Simon - It has. The big problem created by that study was undermining public confidence in a health programme and vaccination. The suggestion was that the babies that have the MMR vaccine might be at increased risk of developing autism subsequently, as if the vaccine was causing the autism. Subsequent studies have not borne out any of the evidence for this link. In countries where the triple vaccine has been withdrawn, the rates of autism haven't really changed. And if you compare countries where a section of the people have had the vaccine and a section who haven't, the rates of autism are very similar in those two groups.

Chris - There was a massive study done in Japan fairly recently where 30 000 people who didn't have the vaccine were compared with people who did. They found that those without actually had a higher rate of autism, suggesting that the MMR is totally unrelated to the rates of autism.

Simon - That's right, and in contrast, an alternative theory of autism is that the condition is genetic. An incident or an event like a vaccine may not be relevant at all.

Anna - Autism is supposed to be an extreme male brain. Is that in any way linked to what you actually look like? Do you have a more male face or more masculine features if you have a more male brain?

Simon - Not necessarily. You can look at the sex of the brain in the sense of 'is it typical?' for a male or a female group. That may be completely unrelated to your outward physical appearance.

Chris - Synaesthesia. It's a tremendously long word, but what does it actually mean?

Simon - It actually means a mixing of the senses. Whereas most people can separate what sense they are currently experiencing, in people with synaesthesia you get this mixing. They may be listening to speech or music, and that triggers, for instance, the experience of taste or colour, so they can no longer keep track of which sense is active.

Chris - Do we have any clues as to why people get this?

Simon - Well we know that it is more common in females, and we also know that it runs in families. So our best guess at the moment is that it's genetic. Having said that, we don't yet know which genes are involved, but there's a project going on in Oxford at the Wellcome Institute of Human Genetics trying to track down the very genes that might be involved.

Chris - We now have Richard on the line who has synaesthesia. What's it like?

Richard - It's something that I basically don't choose to do, it just happens. It's not like waking up one morning and saying 'I'm going to see the world in colour today', I just do it. I experience that certain words, numbers days of the week and months of the year are in colour in my brain. So March is a pale yellowish colour whereas April is a deep red colour. I discovered I had synaesthesia when my wife walked in one day and said that she'd just heard our three children talking about what colour the days of the week are. I told her that that's what I do! Mondays are blue, Tuesday is a deeper grey. She thought that I was a bit odd, and so were the children, but I thought that everybody did it or nobody did. I didn't think it was anything to get excited about. However, a few years back I heard a programme on the radio that was detailing synaesthesia. I realised that this was what I had.

Chris - What do you find it does for you, because some people who have synaesthesia find that it affects the way they see the world and it makes them more creative.

Richard - Well I am a poet and have published my own collection of poetry. I do perform quite a lot in the Yorkshire area. Possibly it's a creative process. I understand metaphors and I've been reading poetry from a very early age and I've never had any problem with it. I also think that it's an important memory aid. It's very easy for me to recall events that happened 35 years ago because I think it goes hand in hand with a photographic memory. I have instant recall with something like photographs in the head.

 

March 2005

Genes And The Brain

DO THEY MAKE US INTELLIGENT? - Professor Seth Grant, Sanger Institute, Hinxton, Cambridge Chris - Tell us how genes are involved in the nervous system. They obviously are because the brain is one of the most metabolically

Seth - Well I think there are rally two exciting things to think about. The first is this: how do all of those genes that are in all of our DNA (that's about 20 000 of them), how do they make our fantastically complicated brain? And just because we now have the whole of the human genome sequence, we can now start to answer that question. We really don't know at the moment. The other thing that really baffles a lot of people is what genes do in behaviour? People like to think that there's a gene for this and a gene for that, but what we're now finding is that there isn't really any such thing. It turns out that there's actually a whole set of genes, and what we can now say is 'what do all those genes have in common?' This makes us look at the different parts of the brain that might underlie these sorts of behaviours. That's one of the most interesting things now.

Chris - What experiments have you done to try and track down some of the genes that are involved in this?

Seth - Well the members in my group have been trying to find out the molecular basis of learning and memory. One of the amazing things that we've discovered is that a heck of a lot of the genes that are important for learning and childhood learning disabilities all make proteins that are part of a single machine. In the same way that you think of a motor car being made up of wheels and all sorts of bits and pieces, all different sorts of genes are all built together into this thing which is like a molecular automobile in your brain which allows you to learn.

Chris - Have you found any genes that are particularly interesting?

Seth - Oh gosh, lots of them! It's really a very exciting thing at the moment, and we're discovering lots more genes. As part of a big programme we have called the Genes to Cognition Programme at the Sanger Institute, we're systematically studying these genes. With clinical colleagues we're examining humans, and with other experiments in mice we understand the basic mechanisms. One gene we studies recently is very important in learning in boys with a form of a very specific learning disability. It turns out that mice with the same gene mutation also have the same learning disability.

Chris - It's interesting that a very different animal has exactly the same deficiency as a human. Presumably animals can teach us a lot about how our own brain works because of exactly this kind of work.

Seth - Yes indeed. There's a lot we can learn by studying animals. But let me bring up something that we've been looking at lately, which is the evolution of behaviour and where does it all come from. I can tell you that one of the new approaches to this is to say that as we've found all these genes important to learning in a mouse and in a human, we can look at when they first evolved. It turns out that some of the genes that are involved in human learning actually evolved before humans evolved themselves. They arose when they were single celled animals. Single celled animals then evolved to become these multi-cellular worms and then flies and other things. And as evolution progressed, we actually developed some new genes that evolved with learning. So some learning genes are very very ancient, while some a very recent.

Chris - It's also interesting to note that everyone in this room shares 60% of their genes with a banana, which Steve Jones was kind enough to tell me when I interviewed him a while back.

March 2005

	If left handed people are made to write with their right hand, will it cause confusion in the brain? I wondered whether it was a good comparison, because at the age of ten I lost my sight and went to a school for the blind. At that time we had to write with a stylus so the writing came out on the other side of the paper. We had to write from right to left in reverse letters. Diane
	I'm not sure it causes confusion in the brain. It doesn't make them very happy though. It's not a nice thing to do any more than it is to make someone do anything that they wouldn't naturally do. There used to be an idea that it mixed up the circuitry in the brain, but I think the circuitry in the brain is a bit more fixed than that.
	March 2005

	I was 35 when I realised that I had synesthesia but no-one in my family has it. I was wondering if it was the brain tumour I had when I was young that triggered it off? Diane
	For most people that we've met that have synesthesia, it has started when they were very young. It was therefore likely to be there before you had a tumour.
	March 2005

	How many cells are there in the brain, and how powerful is a black hole? Alex
	We think it's the old fashioned billion (1012), which is a lot. But guess what your brain is mostly made of? It's actually not nerves. For every nerve cell there are ten other cells that are not nerves and they're there to hold it all together like a scaffolding. As for black holes, they are very very powerful. The reason we know this is because it's black. The reason it's black is because it has such a powerful magnetic field that it can't even let light escape. So when light goes past a black hole, it sucks it in like a giant hoover and makes it disappear. That's why it looks black. I can't really answer exactly how powerful a black hole is because the universe is so enormous that if I say that a black hole is 'x' powerful, there will always be one somewhere more powerful that we haven't discovered yet. So I'm going to sit on the fence and say that I can't answer that.
	March 2005

	Is left handedness genetic, and are left handed people more artistically creative? Theresa
	It's almost certainly genetic, but it's not very obvious always. And yes, they can more talented, especially mathematically and in the visual-spatial arts. Different people have their brains organised in different ways. The genes Seth was talking about wire people up in different ways and make different combinations. We tend to assume that every brain is the same as every other brain, but every brain is fundamentally different. This gives some of us talents in one thing but make us not so good at others.
	March 2005

	Why do you hear your own voice differently to other people? Catherine
	I think what she's getting at here is that if you listen back to a recording of yourself you sound subtly different to how you think you sound. When you listen to a person speaking, the air transmits the sound, goes into my ear and wiggles the ear drum and the bones of the middle ear and eventually makes electrical impulses. When I hear myself speaking, the sound not only goes through the air but also through the bones of my skull. So when my jaw is moving I'm making the bones vibrate directly, and therefore it sounds different. That's probably the explanation.
	March 2005

	How did the American chicken live for seven years with its head chopped off? John
	When its head was chopped off, a tiny part of the head called the brain stem, which links the spinal cord to the top of the brain, was left intact. That's the part of the brain that control breathing, circulation and heart rate, so the chicken had just enough brain left to keep the physiological processes going. They fed it with a tube down its neck for seven years.
	March 2005