Animal Cloning

Animal Cloning

What is Cloning?

• The process of producing genetically identical cells or organisms from the cells of an existing organism.
• Natural clones occur in humans and other mammals as identical twins.
• The two types of artificial cloning used for animals are reproductive cloning and non-reproductive cloning.
• 

Reproductive Cloning

• Reproductive cloning is a type of cloning used to make a complete organism that’s genetically identical to another organism.
• 
• Caption: Dolly was a female domestic sheep, and the first mammal cloned from an adult somatic cell, using the process of nuclear transfer.

Non-Reproductive Cloning

• Non-reproductive cloning is a type of cloning used to make embryonic stem cells that are genetically identical to another organism. Its also called therapeutic cloning.
• 

Nuclear Transfer

• A technique for cloning animals which involves taking a nucleus from an adult body cell and inserting it into an enucleated egg cell. Both reproductive and non-reproductive cloning use nuclear transfer.
• 

Nuclear Transfer

Nuclear Transfer

• A body cell is taken animal A. The nucleus is extracted and kept.
• An egg cell is taken from animal B. Its nucleus is removed to form an enucleated egg cell.
• The nucleus from animal A is inserted into the enucleated egg cell - the egg cell from animal B now contains genetic information from animal A.
• The egg cell is stimulated to divide and an embryo is formed.
• In reproductive cloning the embryo is implanted into a surrogate mother. A infant is produced that's genetically identical copy from animal A.
• In non-reproductive cloning stem cells are harvested from the embryo. The stem cells are genetically identical to the cells in animal A.

Advantages and Disadvantages

• Advantages:Desirable characteristics are passed on
• Infertile animals can be reproduced
• Cloning can happen at any time - wouldn’t have to wait for breeding season
• Repopulate endangered animals
• Aids in medical research - all subjects standardised
• Disadvantages:
• Undesirable characteristics are passed on
• Some evidence suggest clones don’t live as long
• Reproductive cloning is difficult, time-consuming and expensive
• Genetic diversity is decreased
• Susceptibility to disease

Ethical Issues of Human Cloning

• There are many ethical issues surrounding the issue of human cloning. Reproductive cloning of humans is currently illegal in the UK, however, non-reproductive cloning is allowed under licence. Ethical issues include:
• Some believe that it undermines sexual reproduction.
• Some believe clones may have a lower quality of life due to social exclusion or difficulties developing their own personality.
• Unknown psychological effects to the clone.
• Puts both the surrogate and clone at risk as many cloning experiments have resulted in failures in the form of miscarriages, stillbirths, and life-threatening anomalies.
• Some evidence suggest that clones may have shorter lifespans.
• Might foster an understanding of people as objects that can be designed and manufactured to possess specific characteristics. Decrease the value of human life.
• The use of human embryos as a source of stem cells is controversial as the embryos are usually destroyed after they have been harvested.