3.5.4

Cloning

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Cloning

Clones are groups of genetically identical organisms, derived from a single original parent cell.

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Clones

  • When a single parent is able to produce exact genetic copies of itself, clones are produced.
  • This can happen at the cellular and organism level.
  • For example, when bacteria reproduce through the process of binary fission, they are producing clones.
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Natural cloning

  • Many plant species and some animal species have natural methods of cloning.
  • Humans can produce identical twins which are monozygotic. This means they were formed from the same zygote, therefore sharing the same DNA and being clones of each other.
  • Some plants, like strawberries, produce runners which allows them to produce clones of themselves.
  • Other plants, such as potatoes, produce tubers which can then grow into clones of the original plant.
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Embryo splitting

  • Animals can be cloned at the embryo stage by breaking up the embryo into more than one group of cells.
  • When an embryo splits naturally this produces identical twins; however, this can also be done artificially e.g. in order to produce larger numbers of a desired animal.
  • For example, when a bull and a cow with desirable traits are mated the embryo produced will be split into several clusters of cells which can then be implanted into a number of surrogate mother cows. The resultant calves are all clones of each other.
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Cloning of adult animals

  • Cells from adult animals can be harvested and their DNA used to grow a clone of that animal.
  • The nucleus of the harvested cell is placed into an enucleated egg cell.
  • A small current of electricity is then used to stimulate growth.
  • The egg cell can then be implanted into a surrogate mother.
  • The offspring created will be a clone of the original animal whose cells were harvested.
  • Dolly the Sheep was famously produced in this way.

Jump to other topics

1Cell Biology

2Molecular Biology

3Genetics

4Ecology

5Evolution & Biodiversity

6Human Physiology

7AHL: Nucleic Acids

8AHL: Metabolism, Cell Respiration & Photosynthesis

9AHL: Plant Biology

9.1Transport in the Xylem of Plants

9.2Transport in the Phloem of Plants

9.3Growth in Plants

10AHL: Genetics & Evolution

11AHL: Animal Physiology

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