Genetic/Biology Mutations Given the following peptide chain.?

[Cody Baumgartner]

Position48210233234
Normal …..Glu…………...………Gly…………..Gly…..Ser
Mutant ……Val…………...………Arg………….Cys…..Leu

At 210, there can be a second mutation where Arg is mutated into Ile, Thr, or Ser.

a. Assuming that only single base substitutions happen at each step, use the genetic code to explain how the original mutation at 210 (Gly to Arg) can result in Ile, Thr, Ser or Gly from the second mutation.




b. From what you can infer of the nucleotide sequence in the wild-type gene, show, for the codons specifying amino acids 48, 210, 233, and 234, how a nonsense mutation could be generated by a single nucleotide substitution in the gene. (Hint: use the mutation information to
narrow down what the wild-type must be.)