Putting Mendel in His Place: How Curriculum Reform in Genetics and Counterfactual History of Science Can Work Together

Classical or transmission genetics is the study of patterns of inheritance: how traits in an organism – and, either implicitly or explicitly, the genes that give rise to those traits – are passed from one generation to the next. For most undergraduate students, their fi rst (and sometimes only) experience of the study of inheritance is bound up with Mendelian principles. Anyone who has studied genetics at high school or fi rst year at university will be very familiar with Mendel’s peas: varieties of the garden pea with clear-cut, dichotomous traits such as smooth seeds versus wrinkled, yellow seeds versus green, or tall habit of growth versus short. Explanations of the way these traits are transmitted between generations, especially in the pedagogical context, have traditionally been framed around the concepts of dominance and recessiveness . For example, when a smooth-seeded plant is crossed with a wrinkledseeded one, the offspring are all smooth-seeded. Smooth is therefore said to be dominant to its recessive partner, wrinkled. In the same way, yellow is dominant to green, and tall is dominant to short. Further, the ‘gene for’ the smooth trait is taken to be dominant to the ‘gene for’ the wrinkled trait, and so on. This Mendelian approach in the teaching of genetics has persisted into the twenty-fi rst century despite the increasing recognition in many disciplines – genetics, molecular biology and neuroscience amongst others – that, contrary to the Mendel’speas picture, genes should not be regarded as the sole causes of organismic (‘phenotypic’) traits, but rather as elements in a complex network of factors involved in the development of an organism. Of course teaching methods and materials in the sciences always lag behind the sciences themselves, for well-known reasons. In the genetics case, moreover, the start-with-Mendel pedagogic strategy has its defenders Putting Mendel in His Place: How Curriculum Reform in Genetics and Counterfactual History of Science Can Work Together