Toutomerism is the process by which point mutations take place at the gene level by the chage in molecuylar rearrangeme in the bose pairing of uncleotide.
This is the process involved in the chage in the base pairing rather than the normal. That in a DNA molecule instead of binding adenine with thymina and guanine with cytosine, the bases can bind alternately by tautomeric shifts. This occurs due to the shifrs in electrons or protons in the normal nitrogen bases to convert themin their rare states or tautomers.
Thus due to tautomeriztion the amino forms cytosine and adenine may convert into imino tauromer and likewise the keto forms of thymine and faunine convert in to enol tautomers.
Tautomers loss their linkage capacity with their normal partners. Thys adenine linked with cytosinen and guanine linked with thyamine.