Using Colored Pop-beads and Four-Sided Dice to Simulate Genetic Drift

 

Douglas P. Jensen

Tested Studies in Laboratory Teaching, 2015, Volume 36

Abstract

The process of genetic drift is one of the more difficult of the classical evolutionary mechanisms for students to grasp. While students generally understand the concept of genetic drift as it occurs in ecological bottlenecks and the founder effect, its occurrence in randomly breeding populations can appear very abstract to some students. Nevertheless, it is one of the most important processes in evolution, as it plays a crucial role in the Neutral Theory and is applied to many evolutionary problems. I have developed a simple method to model genetic drift through random mating in the classroom. The model can be done within the course of a single class period to help students understand the process on a micro-level in a small population. The model can then be expanded to multiple genes or multiple populations. Ultimately it is intended to serve as a bridge to more important computerized models, applications and theory, and a stepping stone to classroom discussions. In this model, connected pairs of pop-beads represent individuals in a randomly breeding population. The bead colors represent alleles of a gene. Working in groups of two or three, students randomly breed pairs of individuals, produce pre-determined numbers of offspring from each mating, and follow the frequencies of alleles through several generations.

Keywords:  genetic drift, evolutionary mechanisms, randomly breeding populations

University of Oregon (2014)