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How to use The big picture

Ted's teaching tips.

Harmless-looking cress seeds. Or are they? In the 21st century should the many possible techniques of genetic modification be applied? This innocent-looking picture illustrates the minefields amid the techniques, consequences and ethics of science.


What are genes ("messengers" that pass on the characteristics of plants and animals to the next generation)? Where are they found (in chromosomes, the threads inside a cell)? Write down some of your family's characteristics on a piece of paper (eye colour; head shape; hair colour; temperament, fiery or placid; height). Which are affected by environment (inherited intelligence may be stimulated or suffocated, but eye colour will not change much)?

Modifying nature.

What is genetic engineering (modifying or re-combining DNA by, for example, removing a "bad" gene that carries a disease, and replacing it with a "normal" gene)? How can it be applied (producing plants with certain characteristics; cloning; production of biological compounds such as insulin)? What are the risks (unexpected outcomes, if insects transport pollen from a GM crop to somewhere outside the experiment)?


What are ethics (moral rules, right and wrong)? Should animals (such as Dolly the sheep) and people be cloned (a perfect replica, not the product of two parents)? What about other "artificial" techniques, such as in vitro fertilisation (test tube babies)? What if a surrogate mother, who is not the natural parent,changes her mind and wants to keep the baby? Should that be allowed, or should the genetic mother have rights?


Cress seeds grow quickly, so a "generation" is short - hence the attractiveness to gene researchers. Put cress seeds on pieces of dry and wet cotton wool, some in a fridge, some by the radiator. Which grow, and why (warmth, moisture)? How long does it take?

Ted's talking points.

Should we mess around with genes? Is genetics the next scientific revolution, or a dangerous game whose rules we do not yet understand?


Gene therapy is just the next in a long line of scientific developments that have benefited people, animals and plants. It will allow us to eliminate diseases and produce better food for ourselves and for developing countries. All scientific experiments carry a risk, but it is usually small. Safeguards can be built in and ethical issues resolved by good sense. People feared that astronauts would bring back killer viruses from space, but they never did.


Genetic modification is dangerous because it can lead to unpredictable mutations. Suppose, by accident, a deadly plant or animal emerged that wiped out the planet. It is not like cross-fertilisation and breeding because it isn't a natural process. Tampering with genes is playing God and humans should avoid that. Most diseases can be treated by other means, so it is not worth the risk.

Ted Wragg is professor of education at the University of Exeter.

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