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B1b 6 Variation 6.3 Cloning
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Learning objectives What is a clone, and why and how are they created?
What are the risks of cloning?
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Attack of the Clones The creation of a genetically identical copy of an existing or previously existing organism Produced asexually Naturally done by many plants
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Cloning Plants Gardeners have been at it for 100s of years
Ensure that plant has qualities you desire Spiders plants – produce rooting side branch (stolon) – becomes independent Take a cutting – stem or leaf Keep in the correct environment (damp) Roots are produced Clone Commercial technique
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Cloning tissue Tissue culture – produces 1000’s of plants from one cutting 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?
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Hello Dolly Dolly the Sheep Created/born 1996
From a mammary gland cell Since then Monkeys Cats Bulls Horses
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Cloning animals – why?
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Cloning Animals – how? Embryo transplants
A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers.
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Cloning animals – how? Fusion cell cloning Take egg from one organism
Remove nucleus Genetic info Replace DNA Start cell division Implant into ‘mother’
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Pros and cons Bring back extinct/endangered animals
Pets or prize animals Clone animals which produce useful proteins Medically useful Reduces variety in a population 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?
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Learning outcomes Genetically identical offspring produced asexually are clones Easy in plants Cuttings Tissue culture Cloning animals Embryo transplant Fusion cloning
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Selective breeding Friesian Jersey Hereford
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. Jersey Hereford If, for example, I want lots of milk I would only breed Friesian cows with each other – this is SELECTIVE BREEDING.
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Selective breeding vs. Cloning
Advantages Disadvantages Cloning Selective breeding
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