In PCR, what are the functions of DMSO?

DMSO (Dimethyl Sulfoxide) is an organic molecule that has several important functions in PCR. It lowers the melting temperature and prevents annealing, thereby reducing secondary structures, enhancing PCR amplification and increasing the specificity and yield of the reaction. 

PCR reactions require a high melting temperature. This often damages the templates and also prevents accurate primer bindings. When DMSO is added to the reaction, it lowers the melting temperature during the reaction, which promotes primer annealing. 

DMSO also binds with DNA and inhibits reannealing of denatured DNA. This enables primers to get wider space to accurately bind at their correct complementary locations, resulting in a higher number of amplicons.