Non-Neutral Evolution: Theories and Molecular Data

All organisms—from the AIDS virus, to bacteria, to fish, to humans—must evolve to survive. Despite the central place of evolution within biology, there are many things that are still poorly understood. For Charles Darwin, the driving force behind all evolution was natural selection. More recently, evolutionary biologists have considered that many mutations are essentially neutral with respect to natural selection. Many questions remain. Are molecular differences between species adaptive? Ar...