Selective Breeding, Genetic Modification and Cloning

Question 1

How does the process of micropropagation produce clones of a plant?

Answer 1

• Cells known as explants are scraped from the plant you want to clone
• They are sterilised, and transferred to a petri dish containing nutrients
• They will each grow into a small mass of cells known as a callus, and then each callus is added to a larger volume of nutrient medium with growth hormones to encourage the growth of roots, a stem and leaves
• The new plantlets formed are then transferred to soil, giving you a cloned plant

• You must always keep the plants until optimal conditions, such as keeping the environment sterile ot prevent bacterial competion
• This is like taking cuttings, however on a larger and more scientific scale

Question 2

What are the advantages and disadvantages of micropropagation?

Answer 2

• A plant with very desirable characteristics can be quickly cloned with a gurantee the new plants will possess its characteristics
• If you have genetically modified it, this only needs to have been done once
• The desired plant will result in a greater yield, better food, ect. and grow faster
• However it is very expensive and trained personal and laboratories are required
• The organisms are also all genetically identical so won’t adapt to changing conditions and will be vulnerable to disease

Micropropagation can be used commerically to mass produce plants with desired characteristics

Question 3

What is the process of cloning animals?

Answer 3

• A nucleus from a body cell of the organism you wish to clone is extracted
• An unfertilised egg cell is extracted from a female of that organism and the nucleus is removed
• The nucleus from the original organism’s body cell is then inserted into the enucleated egg cell, and a small electric shock stimulates the egg cell to begin dividing to form an embyro
• It is then inserted into the womb of a surrogate mother, which could be any female of that organism
• The resultant organism is genetically identical to the first organism, and possesses no DNA from any other source

This has been done in real life as illustrated by Dolly the Sheep in 1996

Question 4

What are the advantages and disadvantages of cloning animals

Answer 4

• Agricultural animals with desired characteristics can be produced rapidly with a guarantee they will possess the same genes, so genetic modification does not need to be repeated
• Yield and quality of animals is therefore increased
• Rare species can be preserved
• However the new population is less adaptable and are vulnerable to disease
• There are many ethical concerns especially as this could lead to the cloning of humans

Question 5

How can animals be used for producing human proteins?

Answer 5

• Similar to bacteria producing insulin, an animal such as a sheep is genetically modified, making it into a transgenic organism
• This organism now possesses a gene or genes which allow it to produce a specific protein useful to humans, and can be cloned to produce many of this animal
• An example is GM sheep that produce milk containing human antibodies for fighting cancer