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29th Apr 2007
Migrating Genes, Surnames and Y Chromosomes
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This week we're exploring how populations come by their genes including the surprise finding of African DNA in a remote village in Yorkshire. Oxford University's Bruce Winney explains how studying rural populations in Britain is helping to uncover genes linked to different diseases, and Turi King, from Leicester University, discusses what your Y chromosome says about your surname. Plus we'll be hearing how Cambridge scientist Mike Majerus is putting evolution to the test with the help of the peppered moth, and in kitchen science, more jam tomorrow as Ben and Dave show you a trick with a rolling jar.
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News
A 300 million year old fossilized forest has been discovered in a coal mine in Illinois, USA. Covering an area of 10 square kilometres, its the largest fossil rainforest ever discovered and contains a diverse selection of extinct flora.
So how does a forest end up in a coal mine and what can the ex...
As it looks like we’ll be running out of oil in the not-too-distant future, scientists have been hunting for an alternative to fossil fuels for use in cars and other vehicles. Some cars around the world are already running on ethanol, produced from crops such as corn. But it’s expensive ...
It may not seem like an obvious treatment for epilepsy, but results from a team at Johns Hopkins Medical Institute have found that a chemical in anti-dandruff shampoo might be useful for treating the illness. Epilepsy occurs when nerve pathways in the brain “short-circuit”, and nerves st...
In the constellation Libra, 20.5 light years away there is a star we call Gliese 581. This is a small rather dim star which astronomers have been studying for several years, and had found two large planets circling it. One at 15 times the mass of the earth orbiting every 5.4 days and another 8 times...
You may remember at school someone being charged up by a Van de Graaf generator, and their hair standing on end because all the hairs now repel each other.
Engineers at Phillips may have come up with a way of using this principle to make a display out of fabric. The idea is to make a hairy fabric w...
Kitchen Science
Race Jam Jars down a slope and find out that all things don't allways fall at the same speed.
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Interviews
Mike Majerus tells us about the peppered moth, cites as an example of evolution by natural selection in action.
Bruce Winney talks about the genes which make up the British people
Turi King talks about how she found African ancestry in Yorkshiremen, and about how your Y-chromosome type can predict your surname
Chelsea and Bob try to answer the age old question 'Why do we buy what we buy?' Does celebrity endorsement work? How much choice is too much?
Questions
Does junk DNA have a purpose?
It now seems that some of the ‘Junk’ is structural, helping to maintain of genes and chromosomes, and that some if it is very important for controlling how our genes work. There seem to be ‘messages’ coming from what was previously thought to be junk which help to control genes, turn them on and off and operate feedback cycles.
There is some evidence that micro-RNA copied from ‘junk’ DNA may be essential in out immune system, and ‘junk’ DNA is now being studied for its effects in cancer.
This is a quite a new field of research, so watch this space!
What makes a cake rise?
When making a cake you use baking powder or bicarbonate of soda, (or use self-raising flour, which already contains baking powder). Bicarbonate of soda contains carbon dioxide, which can be released as a gas by reacting it with acid or by heating. As the carbon dioxide is much bigger as a gas than it was in the bicarbonate of soda, it expands, makes bubbles in the cake mix and so makes the cake rise.
Another way is to beat lots of air into things containing eggs, such as a soufflé. As you cook the beaten eggs the air trapped in the bubbles expands, making the soufflé rise. (The air bubbles contract again as it cools, which is why the soufflé sinks!)
Why don't ducks get hypothermia?
Ducks have very little muscle in their feet, mainly tendons. This means that the muscle which makes them move is further from the feet and better insulated, and there's less in the feet to keep warm. Ducks also have a very clever circulation system, where warm blood going down to the feet goes closely past the cold blood coming back from the feet. This is called a counter-current heat exchange as heat is exchanged from the hot blood to the cold, meaning that the birds do not lose too much heat through their feet.
There is some suggestion that they also make an anti-freeze compound in their feet called Ethylene Glycol, which stops the blood in their feet from freezing by lowering it's freezing temperature. Natural anti-freeze chemicals are often seen in fish that live in freezing waters.
Whydo geese fly in a v formation?
As a bird’s ( or aeroplane ) wing passes through the air, in order to hold itself up it creates a high pressure area of air below it's wing and a low pressure area above. Air will try and cancel this out by leaking around the end of the wing. This wastes energy and reduces the amount of lift the wing makes (this is why modern aircraft have vertical foils at the end of their wings to try and reduce this).
The air rushes up around the end of the wing and swirls around, creating a vortex behind each wing tip. This wastes energy for the bird in front but if a second bird flys slighty behind and outside the first bird, the air will be moving upwards. So it will actually give a bit of extra lift, for free, to the second bird, reducing the energy needed for flight.
As flying at the front is more tiring than flying further back, migrating birds actually take it in turns to go at the front, so no one bird gets too exhausted.
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