Transcript B1b 6 Variation

B1b 6 Variation
6.3 Cloning
Learning objectives
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What is a clone, and why and how are they
created?
What are the risks of cloning?
Attack of the Clones
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The creation of a
genetically identical
copy of an existing or
previously existing
organism
Produced asexually
Naturally done by many
plants
Cloning Plants
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Gardeners have been at it for 100s of years
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Spiders plants – produce rooting side branch
(stolon) – becomes independent
Take a cutting – stem or leaf
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Ensure that plant has qualities you desire
Keep in the correct environment (damp)
Roots are produced
Clone
Commercial technique
Cloning tissue
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Tissue culture – produces 1000’s
of plants from one cutting
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Much more expensive
Small group of cells chemically
treated with hormones
Cells reproduce
Grow into a new plant
Guarantees characteristics
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Why is a cutting the same as it’s parent plant?
Hello Dolly
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Dolly the Sheep
Created/born 1996
From a mammary gland
cell
Since then
Monkeys
 Cats
 Bulls
 Horses
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Cloning animals – why?
Cloning Animals – how?
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Embryo transplants
A developing embryo is “split” before the cells specialise and
the identical embryos are implanted into host mothers.
Cloning animals –
how?
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Fusion cell cloning
Take egg from one
organism
Remove nucleus
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3.
4.
5.
Genetic info
Replace DNA
Start cell division
Implant into ‘mother’
Pros and cons
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Bring back extinct/endangered animals
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Clone animals which produce useful proteins
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Medically useful
Reduces variety in a population
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Pets or prize animals
If one does have useful mutation, none will
If one has bad mutation, all will
Cloning humans – who would you clone?
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How might fusion/adult cell cloning be useful?
Learning outcomes
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Genetically identical offspring produced
asexually are clones
Easy in plants
Cuttings
 Tissue culture
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Cloning animals
Embryo transplant
 Fusion cloning
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Selective breeding
I raise cows. Each type of
cow is good at a certain job.
The Friesian cow produces
large quantities of milk, the
Jersey cow produces very
nice milk and the Hereford
cow produces lot of beef.
Friesian
Jersey
If, for example, I want lots of
milk I would only breed
Friesian cows with each other
– this is SELECTIVE
BREEDING.
Hereford
Selective breeding vs. Cloning
Advantages
Cloning
Selective breeding
Disadvantages