Post-translational modifications of the CAAX motifs determine the subcellular localization and correct biological function of Ras proteins.

#Id: 2588

#Unit 13. Methods in Biology

In case of nested PCR, the inner primers have a lower annealing temperature than that of the outer pair. For the initial several cycles of PCR the higher denaturation and annealing temperatures are used; as a result, only the outer pair of primer is able to prime amplification. 

#Id: 2589

#Unit 13. Methods in Biology

Nested PCR follows the 'drop in drop out' PCR phenomenon.

#Id: 2590

#Unit 13. Methods in Biology

Touchdown PCR, has been devised to increase the specificity of PCR without lowering the efficiency.

#Id: 2591

#Unit 13. Methods in Biology

Touchdown  PCR is initiated at very high annealing temperatures, which allow only perfectly matched primer-template DNA hybrids to form and support amplification. The annealing temperature is dropped in a stepwise fashion with each cycle of PCR. 

#Id: 2592

#Unit 13. Methods in Biology

The logic for hotstart PCR is as follows, most DNA samples used as template will have some single-stranded DNA. 

#Id: 2593

#Unit 13. Methods in Biology

In case of hotstart PCR, After the reaction mixture is prepared, primers can pair to the single-stranded regions in a nonspecific manner. 

A more attractive alternative is to cover the reaction mixture with a plug of inert wax and place the critical reagent on top of this plug.