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 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

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? Fusion cell cloning Take egg from one organism Remove nucleus Genetic info Replace DNA Start cell division Implant into ‘mother’

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?

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 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.

Selective breeding vs. Cloning Advantages Disadvantages Cloning Selective breeding