Question no 1

Question 12 Consider a large population of fish in a lake who reproduce in discrete generations by a process of random matching. The colour of the fish is controlled by a single gene. Doubly dominant fish TT and heterozygous Tt are silver; homozygous recessives tt are orange. In the population as a whole it is observed that the silver fish outnumber the orange fish in the proportions 11:5. (a) What proportion of the population are heterozygous? [4] (b) What proportion of the silver fish are heterozygous? [2] (c) An orange fish and a silver fish of opposite sexes are selected at random. If they produce an offspring, what is the probability that it will be orange? [4] A random selection of silver fish are caught and moved to a new empty lake. The fish in this new lake continue to reproduce in discrete generations by a process of random matching. After several generations it is observed that around one in eight fish in the new lake are orange. (d) Does this observation accord with expectations? 6 (e) What proportion of all t alleles in the new pond occur in orange fish? [4]