CloningSpec 4.6.2.5
| Method | What happens | Used for |
|---|---|---|
| Tissue culture | Small groups of cells from part of a plant are used to grow identical new plants | Preserving rare plant species; commercially in nurseries |
| Cuttings | An older, but simple, method: a piece of the parent plant is used to grow a new plant | Gardeners producing many identical new plants from a parent plant |
| Embryo transplants | Cells from a developing animal embryo are split apart before they become specialised, then the identical embryos are transplanted into host mothers | Producing several identical animals |
| Adult cell cloning | See the steps below | Producing an animal with the same genes as an adult |
Adult cell cloning
- The nucleus is removed from an unfertilised egg cell.
- The nucleus from an adult body cell, such as a skin cell, is inserted into the egg cell.
- An electric shock stimulates the egg cell to divide to form an embryo.
- These embryo cells contain the same genetic information as the adult skin cell.
- When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
Benefits, risks and objections
| Potential benefits | Potential risks and objections |
|---|---|
| Many identical copies of plants or animals with a useful characteristic can be produced | Clones have the same genes, so there is less genetic variation and a single disease could affect them all |
| Rare plant species can be preserved | Some people have ethical objections to cloning animals |
| Plants can be produced quickly and cheaply, all with the desired characteristic | Cloned animals may be less healthy than normally produced animals |
Quick check
Give the three possible causes of variation.
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Genetic causes, environmental causes, or a combination of genes and the environment.
What do all variants arise from?
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Mutations.
When have two populations become two new species?
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When they are so different in phenotype that they can no longer interbreed to produce fertile offspring.
Name one problem caused by selective breeding.
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Inbreeding, where some breeds are prone to disease or inherited defects.
What is a GM crop?
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A crop that has had its genes modified by genetic engineering.