animal cloning

Question 1

what cells are needed for making an artificial clone of an animal and why

Answer 1

-totipotent cells because they can become any type of cell (only source is early embryo)

Question 2

what are the two types of animal cloning

Answer 2

-reproductive= embryo splitting/ cloning or somatic cell nuclear transfer (SCNT)
-non-reproductive = therapeutic cloning

Question 3

explain the process of reproductive cloning by embryo splitting

Answer 3

-The process of embryo twinning produces offspring that are clones of each other but not of their parents

1)desired individuals are selected (male and female)
2)collect egg and sperm from each and fertilize by IVF (in vitro)
3)grow until there are 16-cell embryo in vitro (these are totipotent)
4)split embryo into several separate segments and implant each into surrogate mothers

Question 4

explain the process of SCNT

Answer 4

-The animal to be cloned donates a somatic (body) cell eg. from an udder
-The egg cell is extracted from the egg donor and enucleated (its nucleus is removed by suction and discarded)
-The nucleus from the udder cell is injected into the enucleated egg cell
-The hybrid zygote cell is now treated to encourage it to divide by mitosis
-The embryo is implanted into the surrogate mother for gestation and birth

(egg and body cell taken from two individuals who are phenotypically different to make sure the offspring is a clone of the correct one at the end)

Question 5

explain non-reproductive cloning/ therapeutic cloning

Answer 5

-a technique designed to use cloned cells to replace dead or damaged cells that cause a loss of function in an individual = organ transplants, tissue replacement, scientific research

-Embryos are cloned as in reproductive cloning, but the embryos are removed and subdivided
-Each individual embryo cell is a totipotent stem cell that can be cultured and artificially differentiated into any type of specialised cell

Question 6

what are some arguments for and against animal cloning

Answer 6

for:
-can produce a whole herd of animals with a high yeild or showing an unusual combination of characteristics
-can be used in scientific research, testing medicinal drugs on cloned cells and tissues avoiding using animals or people for testing
-can be used to replace tissues, treat disease
-individuals from an endangered species can be cloned to increase numbers

against:
-lack of genetic diversity = more susceptible to disease or pests
-success rate for adult cell cloning is very poor and the method is expensive
–cloned animals may be less healthy and have shorter life spans
-ethical issues regarding how long the embryo survives and whether it is right to create life simply to destroy it