Insight Plus - Part 5 – Cloning | Текст песни

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Jackie: Welcome to BBC Learning English dot com and Insight Plus - a series first
broadcast in 2001 that looks at the language of issues you hear about in the news.
How far should science go to help the sick and the suffering? Today on Insight
Plus, Lyse Doucet looks into the cloning debate.
Lyse: Cloning is copying, it can be applied to many things but here we are talking about
copy of a living organism. We are all made from billions of cells, and at the centre
of each one are the instructions - the blueprint - for building our bodies which is
stored in the form of a chemical called DNA. There are two types of cloning,
reproductive cloning where a new baby would be created or therapeutic cloning,
that’s about copying just some of the cells. Therapeutic cloning concentrates on
some special cells called stem cells - they’re the powerfully adaptable 'master cells'.
Opinion is deeply divided about whether or not we should develop this technology.
The BBC World Service has been reporting the developments made in this most
sensitive of issues, we hear first from Dr Robin Lovell-Badge of Britain's Medical
Research Council.
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These cells exist naturally in the body and they are there to replace cells that are lost through
natural processes, so you lose skin cells all the time, you lose cells from your intestines - your
guts - and there are stem cells in the brain to replace a few cells which are lost. And normally
the stem cells divide just the right amount to maintain the organ in a good state. But in the
cases where there's accidental damage or a disease which affects a tissue or an organ, then
quite frequently the stem cells aren't able to divide fast enough to replace the damaged tissue.
So it's hoped that by growing them in a test tube, if you like, that they can be now used to
replace lost cells in a person
Lyse: As Dr Robin Lovell-Badge explained, stem cells regenerate tissue. They repair and
maintain our kidneys, liver and other organs. By introducing new stem cells into
the body, scientists hope to renew damaged tissue and even fight illnesses such as
heart disease and Parkinson's - a disease of the brain.
In 1998, American scientists succeeded in isolating and culturing – growing - stem
cells. They unlocked their potential for medical research and treatment. In future
stem cells could be a vital tool in the war to keep everyone well and healthy.
Doctors know that adult stem cells can develop into different cell types. In
Sweden, for example, the neural cells - cells taken from the brain of adult mice -
have been used to generate kidney, heart and liver cells. But researchers aren’t sure
whether adult stem cells are as perfectly adaptable as those found in embryos -
newly created lives. When an egg is fertilised by a sperm, it forms a ball of cells,
any of them can develop into almost any cell in the body. These 'master' cells -
embryonic stem cells - are at the centre of much of the current research.
Why is the procedure is causing so much anxiety? Well, one way of harvesting -
collecting - stem cells is to actually create embryosm, through a process known as
therapeutic cloning. It’s based on a technique pioneered at the Roslin Institute in
Edinburgh, in 1996, Dolly the sheep was born. Dolly was the first mammal cloned
from an adult cell - a nucleus taken from an adult sheep cell and inserted into an
empty egg. The egg's development into an embryo was triggered by a
revolutionary new technique which makes it possible to clone existing animals -
and it could be used to produce human clones.
Once we have perfect copies of ourselves we’ll be able to repair and renew faulty
parts of our body. The transplant techniques we have now sometimes fail - in the
US.
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