An important but frequently misunderstood tool used in population genetics is the mathematical model. Models are used, for example, to explore the influence of various forces on the genetic variation within and among populations. Let’s take a moment to consider what a model is and how it can be used. A mathematical model usually describes a process as an equation. Factors that may influence the process are represented by variables in the equation; the equation defines the way in which the variables influence the process. Most models are simplified representations of a process because simultaneous consideration of all the factors involved is impossible; some factors must be ignored in order to examine the effects of others. At first, a model might consider only one or a few factors, but after their effects have been understood, the model can be improved by the addition of more details. Even a simple model, however, can be a source of valuable insight into how a process is influenced by key variables.

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