cloning mammals

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cloning mammals

Advantages

  • cloning mammals could help with the shortage of organs for transplants. for example, genetically modified pigs are being bred and they could provide suitable organs for humans.
  • the study of animal clones could lead to greater understanding of the development of the embryo, and of ageing and age-related disorders.
  • cloning could also be used to help preserve endangered species.

Disadvantages

  • cloning mammals leads to a 'reduced gene pool' - when there are fewer different alleles in a population. if a population are all closely related and a new disease appears, they could all be wiped out because there may be no allele in the population giving resistance to the new disease.
  • cloned mammals might not live as long - dolly the sheep only lived for 6 years, half as long as many sheep. she was put down because she had lung cancer and arthritis, she was also cloned from an older sheep.
  • the cloning process often fails - it took hundreds of attempts to clone dolly
  • clones are often born with genetic defects
  • cloned mammals immune systems are sometimes unhealthy so they suffer from more diseases

Evaluation

cloning is a type of asexual reproduction. it produces cells that are genetically identical to the original cell. 1) adult cell cloning involves taking an unfertilised egg cell and removing its nucleus (the egg is enucleated). 2) a nucleus is taken from an adult body cell. this is a diploid nucleus containing the full number of chromosomes. 3) the diploid nucleus is inserted into the empty egg cell. 4) the egg cell is then stimulated by a electric shock - this makes it divide by mitosis, like a normal embryo. 5) when the embryo is a ball of cells, its implanted into an adult female to grow into a genetically identical copy (clone) of the original adult body cell. 

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