Good - I can see you are a person of taste and discrimination

the mutation in the DNA that causes the change in the protein is shown below:

SO if we design a molecluar probe such as a beacon to recognise the mutated sequence but not the normal sequence we will be able to detect the presenceof the mutation and hence drug resistance. The PCR will use primers that can amplify both the normal and mutated gene but only the gene that matches the beacon will allow the beacon to unfold during the PCR and fluoresce.The normal gene does not quite match the beacon and the beacon will not bind to it.

This discrimination requires careful testing of the annealing temperature for beacon binding - too low and the beacon will bind to the normal sequence as well - too high and the beacon will not bind to either sequence.

Fortunately there is a kit (again) available where beacons and annealing temperatures have been worked out for you

 

- Use the kit?

- No - I won't bow to commercial exploitation of clinical diagnostics - I will design my own beacons and optimise them.