A particular gene has the codon CTG Which of the following S

A particular gene has the codon CTG. Which of the following SNPs would cause a change in the protein sequence? (Hint: use the codon table available in your textbook, course slides, and or http://openwetware.org/wiki/Codon_table.) G -> T (CTT) T -> A (CAG) C -> T (TTG) All of these

Solution

CTG would will have code CUG in RNA for protein synthesis (U for T in RNA case)

so now CUG gives Leucine

let see what other gives

G -> T (CTT) =CUU=Leucine

T -> A (CAG) =Gluamine

C -> T (TTG) =Leucine

so change of T -> A (CAG) =Gluamine would give entirely new amino acid thus a new protein