QUESTION+1

Recently you have been studying genetics and are now doing work on Biological techniques. This question is designed to help you think about and extend your understanding of some of the concepts.

** Munchin Cat:- ** In 1983 a woman in America discovered a pregnant cat with very short legs. The short legs were later found to be the result of a mutated allele, which caused the shortening and bowing of the long bones.

A similar effect is seen in the corgi and dachshund dog breeds.

When the cat gave birth, half the litter of kittens had the very short legs and half had normal legs.

Selective breeding was used to establish a population of pure-breeding short-legged cats, as molecular biology techniques such as transgenesis and cloning were not yet advanced enough to be used. This breed of cat is now known as Munchkin.

(a) Explain how each of the following methods could have been used to produce the Munchkin breed from the original female cat:

(i) selective breeding (ii) molecular biology techniques.

(b) Compare and contrast the effectiveness of using selective breeding with molecular biology techniques to produce a new breed of animal such as the Munchkin cat.

__Answer ideas:__ 

==== (ii) transgenesis - isolating the gene that codes for short legs in the cat and placing into the zygote so that when it forms, the cat will have short legs. Use restriction enzymes to remove specific gene from DNA taken from a cat with short legs then used the same restriction enzymes on DNA from the zygote so that the short legged gene can be inserted into strand of DNA to put back into the zygote so that a new short legged cat could be formed. ====

====Cloning - By cloning a cat with short legs (original female cat) we would be able to produce other short legged cats as they would be genetically identical to the original female cat. ====