Apologies in advance for asking bit naive question. I have looked up for this concept a lot but didn't find anything. The wikipedia (I know its not authentic all the time, but I think works well for definitions atleast) page on Complementarity says:
The degree of complementarity between two nucleic acid strands may vary, from complete complementarity (each nucleotide is across from its opposite) to no complementary (each nucleotide is not across from its opposite) and determines the stability of the sequences to be together
This is quite new concept for me and how come we can have basepairing between opposite nucleotides if there isn't 100% complementarity? Any evidences behind it?