Explain the concept of a mutation and how mutations can translate to loss or gain of function?

Answer / Explanation

Mutation is a change in DNA sequence which usually occurs as a results of mistakes in DNA replication or exposure to mutagenic agents. Mutations can cause loss of function of a gene, or produce a new function

A loss of function mutation happens when a mutation causes the a gene to have a reduced or lost activity or function. For example, a single base deletion in the coding region of the gene could produce a frame shift mutation, changing all downstream information and creating a useless protein that can no longer carry out its function. Alternatively, a base substitution could change an amino acid. If this amino acid is in an important region, for example a binding site, or a catalytic domain, the protein can no longer perform its tasks.

A gain of function mutation occurs when a change in DNA sequence does not disrupt the function of a protein, but instead adds to its function through increasing its activity or giving it additional abilities. For example, a mutation in a promoter site that means the gene is always being transcribed (constitutively active). Another example could be a mutation that generates a new binding site in the protein, allowing it to interact with new partners.