A polypeptide has the following amino acid sequence
Met-Ser-Pro-Arg-Leu-Glu-Gly
In a mutant the amino acid sequence of this polypeptide was found to be
Met-Ser-Ser-Arg-Leu-Glu-Gly
What is the type of mutation that occurred in the reading frame of its DNA?
A. Silent mutation
B. Nonesense mutation
C. Mis-sense mutation
D. Frame-shift mutation
