Animal Cloning

Question 0

What is reproductive cloning?

Answer 0

• cloning whole organisms that are genetically identical to another organism
• used in biotechnology and agriculture
• can be used to save endangered species from extinction

Question 1

What is non - reproductive cloning?

Answer 1

• it is the use of stem cells to generate replacement cells, tissues or organs which may be used to treat particular diseases or conditions in humans
• the cells are genetically identical to another organism won’t be rejected by patients if they are genetically identical to their own cells

Question 2

Describe how animals can be cloned by somatic cell nuclear transfer

Answer 2

• a body cell is taken from sheep A and the nucleus is extracted and kept
• an egg cell is taken from sheep B and its nucleus is removed to form an enucleated egg
• the nuclear from sheep A is inserted into the enucleate egg cell - the egg cell from sheep B now contains the genetic information for sheep A
• the egg cell is given an electric shock (fission of egg + nucleus) to stimulate it to divide
• cell division continues until it reaches blastocyst stage
• in reproductive cloning the embryo is then implanted into a surrogate mother - lamb is produced that a genetically identical copy of sheep A
• in non - reproductive cloning stem cells are harvested from the embryo - the stem cells are genetically identical to the cells in sheep A

Question 3

Describe how animals can be cloned by splitting embryos

Answer 3

• a female cow is selected that has desirable traits and is given FSH to stimulate egg production
• the eggs are then harvested from the female cow
• sperm is also harvested from a desirable bull
• through IVF (in vitro fertilisation) a zygote is produced
• it is allowed to divide by mitosis to form a ball of cells which are then separated before differentiation starts - they are totipotent
• each cell is allowed to grow and divide again before each new group of cells can then be places into the uterus of a surrogate mother
• this produces many genetically identical offspring

Question 4

What are the advantages of cloning animals?

Answer 4

• high value animals can be cloned in large numbers
• endangered species can be cloned which could increase their numbers
• can produce lots of the same organism quickly

Question 5

What are the disadvantages of cloning animals?

Answer 5

• reduced gene pool - decreases allele frequency
- if one organisms is susceptible to disease all are
• animal welfare issues
• old DNA - premature death