Animal cloning Module 6 Flashcards
How can animal clones occur naturally?
Fertilised egg can split during very early stages of development and develop into multiple embryos with the same genetic information, and develop into offspring which are genetically identical
Eg. identical twins
Steps in artificial embryo cloning for a cow (doesn’t matter which animal)?
An egg cell is extracted from a female cow and fertilised in a petri dish
The fertilised is left to divide at least once, forming an embryo in vitro (outside a living organism)
Individual cells from the embryo are separated and each is put into a separate petri dish, each cell divides and develops normally so an embryo forms in each petri dish
Embryos are implanted into female cows which act as surrogate mothers
Embryos develop in surrogate mothers and form offspring, all offspring genetically identical to each other
Steps in Somatic Cell Nuclear Transfer (SCNT) for sheep(again animal doesn’t matter)?
A somatic cell (any cell that isn’t a reproductive cell) is taken from sheep A. The nucleus is extracted and kept
An oocyte (immature egg cell), is taken from Sheep B, it’s nucleus is removed to form an enucleated oocyte.
Nucleus from sheep A is inserted into the enucleated oocyte, the oocyte from sheep B now contains genetic information from sheep A.
The nucleus and the enucleated oocyte are fused together and stimulated to divide via electrofusion (electrical current is applied) producing an embryo
The embryo is implanted into a surrogate mother and eventually a lamb is born that is a clone of sheep A.
Uses of animal cloning?
Research purposes, can test new drugs, useful as all genetic variation removed
Save endangered animals from extinction
In agriculture, farmers can increase number of animals with desirable characteristics to breed from
Animals can be genetically modified so produce a useful substance they normally wouldn’t
Embryonic stem cells can become any type of cell, so can replace damaged tissue in a range of diseases, works because if embryonic stem cells identical to patient, the immune system won’t reject new ttissue
Arguments for animal cloning?
Desirable genetic characteristics are always passed on
Infertile animals can be reproduced
Can increase population of endangered animals to help preserve biodiversity
Animals can be bred at anytime, don’t have to wait till breeding season
Helps develop new treatments for disease which could mean less suffering for some people
Arguments against animal cloning?
Difficult, time consuming and expensive
Undesirable genetic characteristics always passed on
Whole population susceptible to one disease as genetically identical
Unethical as clones don’t live as long as natural offspring
Using cloned human embryos as a source of stem cells can be seen as destroying a human life
