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Genes
are long bits of
which code the instructions to build bodies in certain
ways. Scientists know a lot about how genes work. They
know how to 'snip' genes out of one place and 'stick'
them into another. This is the hi-tech world of genetic
engineering. We'll look at this in a moment. But first,
let's ask a question or two. Why do it? What's the point
of tinkering with genes - genetic engineering?
Evolution
on fast forward
People are impatient. They want to move fast, not just
in cars, planes and spaceships. They want to make new
types of life which will do new things. The best example
is plants for food. About 10,000 years ago, people found
a new way to make sure they got enough food: they invented
agriculture -- .
The first farmers simply collected seeds of food plants
people liked to eat and sowed them in the ground. Each
harvest, they gathered in their seed crops and selected
the best and fattest seeds to sow in the ground next year.
All organisms -- plants, penguins or people -- have in
their genes a certain amount of variation, so gradually
this year-by-year selection of the best quality seeds
meant that the crops gave better yields of more food which
tasted nicer.
This
is called breeding. And believe it or not, all dogs from huge St Bernards
to tiny Chihuahuas have been selectively bred by humans from one type
of wild dog - probably a wolf. A
St Bernard and a Chihuahua are the same
even though a St Bernard could gobble up a Chihuahua in one gulp. Being
the same species means you can breed with any other member of your species.
So you, a human, can breed - or mate - with any other human of the opposite
sex to make a baby.
But breeding is rather slow. Scientists
have discovered that they can speed things up greatly
by using the new science of genetic engineering, part
of what is called
- using life to make things.
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