The Hardy-Weinberg Equilibrium—Some Helpful Suggestions

Abstract

IN college General Biology curricula, the topic of classical genetics is typically followed by consideration of population and evolutionary genetics. After fundamental genetic principles are studied, students are introduced to the Hardy-Weinberg equilibrium as a continuum of Mendelian Genetics in a population context. Population genetics provides a logical segue to the study of evolution. Populations adhering to the Hardy-Weinberg equilibrium provide a reference for studying evolutionary changes (Journet 1986). With this as a starting point, Darwin’s observations can be justified and quantified, as well as expanded upon, to include additional aspects of population and evolutionary genetics. The Hardy-Weinberg equilibrium is an algebraic mathematical tool for predicting allele frequencies, phenotypes and genotypes in populations (Cummings 1997; Lewis 1997; Mader 1996; Postlethwait & Hopson 1995). Mertens (1992) proposed strategies for introducing the Hardy-Weinberg equilibrium to make it meaningful and more useful to both students and teachers. It has been our experience that students have difficulty with Hardy-Weinberg problem solving. Since students often possess a genuine fear of mathematics, reinforcement of basic mathematical principles when working through Hardy-Weinberg problems will provide a less threatening experience, thereby enabling students to successfully complete problems and concentrate on understanding genetic concepts as they relate to population dynamics (Flannery 1995; Journet 1986). Various methods, some quite detailed, for presenting the Hardy-Weinberg equilibrium have appeared in journals and textbooks (Cummings 1997; Journet 1986; Lewis 1997; Mader 1996; Postlethwait & Hopson 1995). The Hardy-Weinberg model is presented in a variety of ways in General Biology textbooks. In this paper we offer suggestions for instructors to assist with their presentation of this topic. Regardless of the approach, our suggestions can assist instructors by providing a unified method for explaining the