Potassium channel blockers (such as amiodarone and procainamide) are used to treat abnormal electrical activity of the heart. These drugs impede movement of K through voltage fated K channels. Which part of the action potential would you expect these drugs to most directly affect

repolarization  

Explanation:

Potassium channel blockers are drugs that interfere with the flow of potassium ions (K+) through potassium channels in cell membranes, thereby prolonging the duration of the action potential (repolarization phase). For example, amiodarone is a class III antiarrhythmic agent whose target is HERG human cardiac K+ channel. This drug (amiodarone) acts by prolonging the repolarization phase of the cardiac action potential.

identify the dna change shown in the diagram and explain how that change can result in the increased genetic diversity often seen among siblings.