Cloning (4)

Question 1

What is cloning?

Answer 1

Cloning describes the processes used to create an exact genetic copy of another gene, cell, tissue or organism. The copied material, the clone, has the same genetic makeup as the original.

Question 2

In recent years clones have been produced using…

Answer 2

embryonic and non-embryonic nuclear transfer techniques.

Question 3

What is Embryonic nuclear transfer?

Answer 3

This process has been used successfully for many years in sheep, using cells taken directly from early embryos.

Question 4

What can embryonic nuclear transfer produce? (3)

Answer 4

• many transgenic animals with very precise genetic qualities as rapidly and cheaply as possible. These valuable animals can then become part of commercial herds.
• many clones from a single female to conserve animals nearing extinction.
• early embryos from which stem cells can be isolated for use in tissue and cell engineering.

Question 5

What is Non-embryonic nuclear transfer (somatic cell transfer)?

Answer 5

Dolly, the Dorset lamb born in Scotland, was the first mammal to be cloned at the Roslin Institute from non-embryonic cells.

Question 6

Describe the process of Non-embryonic nuclear transfer (somatic cell transfer) (5)

Answer 6

1. In a process called ‘somatic cell nuclear transfer (SCNT), scientists transfer genetic material from the nucleus of a donor adult cell to an egg whose nucleus, and thus its genetic material, has been removed.
2. An electric pulse is used to combine the dormant donor cell and the recipient egg cell.
3. The reconstructed egg containing the DNA from a donor cell must be treated with chemicals or an electric pulse in order to stimulate cell division.
4. Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female host where it continues to develop until birth.
5. The resulting offspring is a clone of the somatic cell donor. Study the diagram below very carefully.

Question 7

Why is this procedure so significant (Non-embryonic nuclear transfer (somatic cell transfer))?

Answer 7

This procedure proved that the genetic material from a specialized adult cell, such as an udder cell of a cow, programmed to express only those genes needed by udder cells, could be reprogrammed into an embryonic state to generate an entirely new organism, not just udder tissue.

Question 8

The most controversial aspect of cloning is the potential to clone humans which creates enormous moral and ethical concerns, e.g. cloning humans could result in: (5)

Answer 8

• the creation of groups of people for specific purposes, e.g. warfare or slavery.
• attempts to improve the human race according to an arbitrary standard.
• clones being created for the sole purpose of using their organs and tissues for transplants.
• the death of many embryos and newborns because the techniques have not been perfected.
• In addition, cloning reduces genetic diversity by reducing the gene pool. This could weaken a population’s ability to adapt to its surroundings.