Do you worry about designer babies and GM food? Do you find the idea of cloning humans freaky? With much of the news coverage talking about ‘Franken-foods', ‘super-breeds' of perfect children and Elvis clones, it is not surprising that many people are anxious about new DNA technologies. Should you be?
Advances in gene technology raises possibilities that, as a society, we haven't previously had to face. But ignoring them won't make them go away. There are many ways that we can now use DNA, but to help us make our minds up on which of these technologies should be pursued we need to have open discussions about all of the issues, and we need to consider the benefits as well as the threats. These are some of the ways in which we use DNA technology. Think about how far you think we should go.
The DNA detective
In 1988, a man was sentenced to life imprisonment for murder. You might think this is not very surprising, but the fascinating thing about this case was the way in which his guilt was finally established. For the very first time, police used genetic fingerprinting (more commonly called DNA profiling) to solve the case.
DNA fingerprinting allows scientists to look at the patterns of DNA we have inside our cells. Because our DNA is unique, it provides an almost perfect means of identification. Even minute samples of blood, semen, saliva or a hair, can reveal the genetic identity of its owner. This is thanks to an incredibly sensitive technique called PCR (short for polymerase chain reaction), which copies particular stretches of DNA at a tremendous rate.
Play the role of a forensic scientist and see if you can help the police in their investigations by doing a DNA Detectives game.
DNA profiling can also decide who the father is, in a paternity dispute. This is because the genetic profiles of parents and children have strong similarities. But powerful as it is, the technique also has its problems. In small communities, where there is a lot of intermarrying, there is less genetic variability between individuals than in the general population. So this must be taken into account when deciding how much weight to give to evidence from DNA profiling.
Can we use genetics to predict diseases?
If you had a faulty gene that will make you terminally ill, would you want to be tested and receive what is essentially a death sentence? Or would you rather live in ignorance? Scientists now have the ability to test for hundreds of genes that, when mutated, can cause disease. The problem is what to do with that information.
Imagine you've just had a baby and doctors want to run a genetic test. They are looking for a defective gene for which there is a simple solution. Would you allow it? Most people do. In fact every baby in the UK is tested for phenylketonuria or PKU, an inborn error of metabolism that can make children mentally retarded but which is remedied with a special diet. Few people object to genetic testing when a therapy for the disease exists.
What about testing for genetic mutations that might increase your risk of developing say, heart disease or Alzheimer's disease? Is testing a good idea? From one point of view, your genetic profile might be useful in allowing doctors to give you a better treatment, but on the other, insurance companies may use this information to raise your premium and you may become unemployable. There's no simple answer.
So why are scientists searching for disease genes? Does it help to know you have a high chance of developing, for instance, breast cancer? For most cancers there is a better chance of dealing with them if caught early so it makes sense to know whether you have inherited a genetic predisposition. In breast cancer, for example, there are two genes that are linked to the disease, although not all women with these mutations develop tumours. The advantage of knowing that you have a genetic predisposition is that you could do things to prevent the disease like taking a medicine or having surgery.
What about human cloning?
If you ask around, most people are appalled at the idea of human clones. Yet chances are, you've probably met one. Surprised? A clone means an exact copy, and nature can produce them too - identical twins. Of course, when people think of clones, most think of the technology that made Dolly the sheep.
Dolly is the first mammal cloned from an adult cell and the most famous sheep ever. To produce Dolly, researchers took the nucleus of an udder cell of an adult sheep and inserted it into an empty egg from another ewe. Once the embryo formed, they implanted it into the uterus of a third animal.
Did You Know...that Dolly's name was inspired by the country-and-western singer Dolly Parton, who is famous for her breasts or mammary glands? This ewe gave birth to Dolly, an exact replica of the sheep that provided the udder cell. Dolly the sheep was a breakthrough because she proved that it is possible to take a cell from an adult animal and switch all the genes back on.
Since then, many more animals have been cloned. What for? Cloned animals give scientists the chance to insert useful genes to produce medically useful proteins in their milk such as blood-clotting factors to treat people with haemophilia. But why clone humans? Cloning could allow a totally infertile couple to have a child that is biologically related. Grieving parents might replace a dead child. It might also become possible to produce copies of highly skilled sportsmen or highly intelligent individuals.
But there is still a lot of risk involved in cloning. The failure rate is very high (about one in 20 implanted embryos die), and those that survive seem to have all sorts of serious problems. Cloned mice become very obese and cloned calves have difficulty breathing and malfunctioning livers. Despite these drawbacks, some rogue doctors have attempted to clone humans.
Is it right to attempt to clone humans before the technique is safe? And even when the technical problems are sorted, is human cloning ethically acceptable? For starters, it would cause very strange family relationships. A child cloned from a parent would be his or her twin sibling. People also fear that cloning might be abused to produce armies of workers or soldiers by unscrupulous governments or companies. Some people argue that cloned people might be branded as inferior, while others object to cloning because they say scientists are ‘playing god' by interfering with the normal mode of reproduction.
GM foods - yes or no?
Do you feel that inserting a fish gene into a tomato is just too weird? Are you worried that genetically modified (GM) food could endanger your health? You are not alone. When it comes to GM food and animals, people feel that scientists are tampering with nature. We accept that adding a few genes here, snip out a few others there, is done routinely in labs around the world. But we object to the manipulation of living things on the grounds that it is unnatural. And it is true, it is unnatural. But so is all technology, including the selective breeding of plants, cattle and dogs that humans have carried out for thousands of years. Just look at Chihuahuas and Great Danes. Humans bred them from the wild species of dog long before DNA technology was invented!
GM food is just as nutritious and looks the same - you'd never taste the difference. But what campaigners against GM foods argue is that modified crops might spread their genes to nearby weeds or organic crops putting the environment under threat. Up to now, there is no convincing evidence one way or another.
Do we need GM foods? For developing countries that struggle to feed themselves, the benefits of GM technology could be enormous. Genetic engineering can make farming more efficient, provide plant varieties that will resist pests, grow in poor soil or survive droughts. For more information about GM crops, take a look at the Royal Institution Christmas Lectures 2005 The Truth about Food.
Did You Know...that scientists have introduced genes into bananas turning them into vaccines against illnesses ranging from rabies and cholera to 'traveller's diarrhoea'?
A good example is the much publicised ‘golden rice' that has been genetically altered to provide vitamin A. Eating this transgenic crop can prevent vitamin A deficiency, a condition that leads to blindness and contributes to the death of more than a million children each year children in parts of Asia, Africa and Latin America.
But is GM food safe? Some people are afraid that GM foods might cause allergic responses and endanger health. Scientists are looking for answers and, until they have them, it may not be possible to assume one way or another what the long-term effects of consuming genetically modified food will be.
For Teachers' Notes on this subject, click here.