Animal cloning, by artificial twinning or somatic cell nuclear transfer (SCNT), has clear uses but also real problems.Advantages
• High-value animals, such as cows with a very high milk yield or prize bulls, can be copied, so good traits are reproduced exactly.
• Artificial twinning gives many offspring from one breeding cycle, more than the parents would produce naturally.
• Rare or endangered animals can be cloned to increase their numbers.
• Pharming: a genetically modified animal that makes a useful protein (for example a drug in its milk) can be cloned to give a whole herd of producers.
• Genetically identical animals are useful in research, because genetic variation between test animals is removed.Disadvantages
• SCNT is very inefficient. Many embryos fail to develop and many pregnancies miscarry, so it is expensive.
• Many cloned animals have health problems and some have shorter lifespans.
• Clones have no genetic variation between them, so a disease or environmental change that harms one could harm them all.
• Cloning endangered animals does not increase genetic diversity, which the population needs to survive in the long term.
• There are ethical concerns about animal welfare, about the high failure rate, and about whether the methods could one day be applied to humans.When judging a use of cloning, weigh the benefit (a product, a saved species, a research result) against the cost in failed embryos, animal health and lost genetic diversity.
• High-value animals, such as cows with a very high milk yield or prize bulls, can be copied, so good traits are reproduced exactly.
• Artificial twinning gives many offspring from one breeding cycle, more than the parents would produce naturally.
• Rare or endangered animals can be cloned to increase their numbers.
• Pharming: a genetically modified animal that makes a useful protein (for example a drug in its milk) can be cloned to give a whole herd of producers.
• Genetically identical animals are useful in research, because genetic variation between test animals is removed.Disadvantages
• SCNT is very inefficient. Many embryos fail to develop and many pregnancies miscarry, so it is expensive.
• Many cloned animals have health problems and some have shorter lifespans.
• Clones have no genetic variation between them, so a disease or environmental change that harms one could harm them all.
• Cloning endangered animals does not increase genetic diversity, which the population needs to survive in the long term.
• There are ethical concerns about animal welfare, about the high failure rate, and about whether the methods could one day be applied to humans.When judging a use of cloning, weigh the benefit (a product, a saved species, a research result) against the cost in failed embryos, animal health and lost genetic diversity.