Rethinking (again) Hardy-Weinberg and genetic drift in undergraduate biology

Area of Science:

• Biology Education
• Population Genetics
• Evolutionary Biology

Background:

• Designing effective science curricula requires careful content selection to maximize student learning and engagement.
• Population genetics concepts, like Hardy-Weinberg equilibria (HWE), can be challenging for introductory students.
• Traditional curricula often include HWE calculations, despite their perceived difficulty and limited introductory relevance.

Purpose of the Study:

• To evaluate the pedagogical value of Hardy-Weinberg equilibria (HWE) calculations versus genetic drift in introductory biology.
• To propose an alternative focus on stochastic processes like genetic drift for better student comprehension and quantitative skill development.

Main Methods:

• Conceptual analysis of curriculum content in introductory biology, focusing on population genetics.
• Comparison of the pedagogical utility of Hardy-Weinberg equilibria (HWE) calculations and genetic drift.
• Examination of the origins of genetic drift in fundamental biological processes.

Main Results:

• Hardy-Weinberg equilibria (HWE) calculations offer limited justification for introductory biology due to their complexity.
• Recessive alleles are not inherently weaker or preferentially lost without selection.
• Genetic drift, arising from meiotic processes, is a ubiquitous and functionally significant stochastic behavior.

Conclusions:

• Introductory biology curricula should prioritize genetic drift over Hardy-Weinberg equilibria (HWE) calculations.
• Teaching genetic drift mechanistically and probabilistically enhances understanding of allele dynamics and quantitative reasoning.
• Focusing on stochastic processes counters deterministic thinking and promotes quantitative skills in biology.