Investigating the causes of changes in allele frequency during evolution

The use of models as teaching aids in the study of the causes of changes of gene frequency during evolution is now a well established practice in school and degree courses. The effects of migration, selection and genetic drift may all be investigated. This paper extends the range of procedures which may be used with sixth form and more advanced students by discussing possible migration models, by describing an improved selection model where selection is applied unconsciously and the selection coefficient can be calculated from the data and by comparing single and multiple generation models.

In each case there is a brief discussion of points to be extracted from class results.

An overall teaching programme is suggested which should enable the students to investigate all three factors while spending a minimum of time on repetitive manual procedures.

Finally, there is a brief discussion of the roles of migration, drift and selection in evolution.