<prompt> Transversion seen inGuanine - cytosineGuanine - adenineGuanine - thymineAdenine - thymine  <response>: SubstitutionReplacement of a purine by another purine A to G or G to A or pyrimidine by pyrimidineT to C or C to T is called transition mutation. If purine is changed to a pyrimidine A to C or a pyrimidine to a purineT to G, it is called a transversion mutation.Ref: Textbook of biochemistry DM Vasudevan, 6th edition, page no. 612 