Varieties of behavioral natural variation

Behavior is flexible at different timescales, modifiable by experience in the short term and by evolution in the long term. In order to understand how behavior evolves, we must both understand how trait differences between individuals are inherited and how a subset of these differences get fixed within a species' lineage. Work over the past few decades has shown that this will not be easy; the genetic basis of heritable behavioral differences between two individuals is typically complex, caused by multiple genetic variants of small effect. Here I describe how the underlying genetic networks impact the types of genetic variants that can be selected for by evolution.

► I highlight some of the different types of genetic differences between two individuals of a species that can modify behavior. ► I summarize lessons learned through the study of the evolution of development and contrast the genetic networks controlling development with behavior. ► Examination of the genes and gene networks that control behavior can illuminate why different types of genetic changes are fixed by evolution. ► This concept is illustrated using evolution of sensory genes.