Due to the mutation in DNA, Sequence of nucleotide can be
altered because of transitions or transversions or deletion or
addition of nucleotides. Due to the mutation, it can produce stop
codon in between gene and further causes the premature chain
termination and hence non functional proteins are produced.When the
number of nucleotides added or removed is not equal to three,
causes a frameshift mutation. Point Mutations may also occur in
non-coding regions - introns or regulatory regions, severity of the
mutation depends upon the region it occurs in, mutations in introns
have little or no effect. Mutation in the gene can also produce
different phenotypes. Because mutations can interrupt cellular
processes, mutants often hold the key to understanding gene
function.