Cloning in plants and animals

In a nutshell

Plants and animals can be cloned to produce genetically identical copies of the original parent. However, there are some issues surrounding these methods.

Plant cloning

Plants can be cloned in two different ways; tissue culture and cuttings.

Method	Description	Advantages
Tissue culture	Cloned plants can be made by putting plant cells into a medium with growth hormones.	Clones can be made quickly and at any time of year. They also require very little space. This method can be used to preserve rare plants.
Cuttings	Select parent plant and take cuttings. Plant the cuttings to produce genetically identical clones of the parent plant.	Clones can be made quickly and cheaply.

Embryo transplants

Sperm cells are taken from one animal and egg cells are taken from another animal. The sperm is then used to artificially fertilise an egg. This produces an embryo which can be split many times to form lots of embryos that are all genetically identical. The embryos can then be implanted into lots of different female animals that will then produce offspring that are all genetically identical.

Example

Biology; Inheritance, variation and evolution; KS4 Year 10; Cloning in plants and animals

1.	Sperm cells are taken from a bull.
2.	Egg cells are taken from a cow.
3.	The sperm is used to artificially fertilise the egg.
4.	Embryos are produced.
5.	The embryos split many times.
6.	The embryos can be implanted into different female adults to produce offspring that are all genetically identical.

Adult cell cloning

This method involves using an adult body cell, like a skin cell, and an egg cell to create a clone of the animal that the body cell originated from. The process is described below.

Example

Biology; Inheritance, variation and evolution; KS4 Year 10; Cloning in plants and animals

1.	A body cell is taken from sheep A.
2.	The nucleus is removed the body cell of sheep A.
3.	An unfertilised egg cell is taken from sheep B.
4.	The nucleus is removed from the unfertilised egg cell of sheep B.
5.	The nucleus from the body cell is inserted into the empty egg cell.
6.	The egg cell is then stimulated by an electric shock which causes it to divide and form an embryo.
7.	When the embryo is a ball of cells, it will be implanted into an adult female's womb.
8.	It will produce a clone of the animal that the original adult body cell came from.

Note: This is the method that was used to produce Dolly, the famous cloned sheep.

Advantages and disadvantages of cloning

There are various advantages and disadvantages of cloning. These are explained below.

Advantages	Disadvantages
Gives a better understanding of embryo development and age-related disorders.	Clones are all genetically identical so there will be fewer different alleles in a population. This leads to a reduced gene pool. If a new disease appeared or the environment changed then the whole species could be wiped out.
May help to preserve endangered species.	Cloned animals may not be as healthy. For example, Dolly the sheep had arthritis which is much more common in older sheep.
	People worry that in the future we may be able to clone humans which they believe is unethical.