This tutorial surveys the ongoing controversy of the neutral theory. The debate concerns the extent to which molecular evolution is the result of selection or neutral drift. In the course of the debate, evidence from many different sources has been argued over: beginning with proteins and amino acids and moving onto genetic observations. This tutorial will take you through the different evidence and arguments over the last thirty years.

Key Questions:

• What is the neutral theory?
• How do we test the neutral theory?
• What limits the rate of evolution by selection?
• What were Kimura's arguments for neutralism?
• Why are Kimura's arguments flawed?
• Why is molecular evolution constant?
• Why do evolutionary rates differ?
• What does the genetic evidence show?
• Is polymorphism correlated with the rate of evolutionary change?
• Summary