The coding strand of some DNA is shown. It is part of a sequence that codes for a polypeptide.Contrast the effect of a frameshift mutation with the effect of a base substitution mutation on the polypeptide produced from this sequence.

A frameshift mutation and a base substitution mutation are two types of mutations that can occur in the DNA sequence and can have different effects on the polypeptide produced.

1. Frameshift Mutation: This type of mutation occurs when one or more nucleotides are inserted or deleted from the DNA sequence. This changes the reading frame of the genetic code, hence the name "frameshift". Since the genetic code is read in triplets (codons), adding or removing nucleotides can change every codon that comes after the mutation. This often results in a completely different polypeptide being produced, as different codons code for different amino acids. In many cases, a frameshift mutation can also create a premature stop codon, which would end the polypeptide chain early.

2. Base Substitution Mutation: This type of mutation occurs when one base in the DNA sequence is replaced by another. This can have different effects depending on the specific mutation. If the new base codes for the same amino acid (due to the redundancy of the genetic code), then there will be no change in the polypeptide produced. This is known as a silent mutation. If the new base codes for a different amino acid, then only that specific amino acid in the polypeptide will be changed. This is known as a missense mutation. If the new base creates a stop codon where there wasn't one before, this is known as a nonsense mutation and would end the polypeptide chain early.

In summary, a frameshift mutation generally has a more drastic effect on the polypeptide produced, as it can change multiple amino acids and often creates a completely different polypeptide. A base substitution mutation can also change the polypeptide, but usually only affects one amino acid and the effect is often less severe.