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B1b 6 Variation 6.3 Cloning Learning objectives What is a clone, and why and how are they created? What are the risks of cloning? 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 Cloning Plants Gardeners have been at it for 100s of years Spiders plants – produce rooting side branch (stolon) – becomes independent Take a cutting – stem or leaf Ensure that plant has qualities you desire Keep in the correct environment (damp) Roots are produced Clone Commercial technique 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 Why is a cutting the same as it’s parent plant? Hello Dolly Dolly the Sheep Created/born 1996 From a mammary gland cell Since then Monkeys Cats Bulls Horses Cloning animals – why? Cloning Animals – how? Embryo transplants A developing embryo is “split” before the cells specialise and the identical embryos are implanted into host mothers. Cloning animals – how? 1. 2. Fusion cell cloning Take egg from one organism Remove nucleus 3. 4. 5. Genetic info Replace DNA Start cell division Implant into ‘mother’ Pros and cons Bring back extinct/endangered animals Clone animals which produce useful proteins Medically useful Reduces variety in a population 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? How might fusion/adult cell cloning be useful? Learning outcomes Genetically identical offspring produced asexually are clones Easy in plants Cuttings Tissue culture Cloning animals Embryo transplant Fusion cloning 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
