The point mutations involve alterations in the structure of gene by altering the structure of DNA. Point mutations are of two types-(i) base pair substitution and (ii) frameshift substitution. Insertion is the addition of one or more nitrogenous bases to a nucleotide chain. Duplication is the presence of one block of genes more than once in a haploid component. Deletion is the removal of one or more nitrogenous bases from a nucleotide chain.