Is it time to remove Mendel from the school curriculum?

Gregor Mendel has been at the heart of secondary school genetics for as long as I can remember. I taught Biology in schools for 40 years and we were encouraged and expected to begin with Mendel’s work on peas. It made sense. After all, in the UK it’s how textbooks introduce 14–16 genetics and where the specifications always started. Keep it simple: a single gene with two alleles, one of which was dominant, determining a single character. A nice exact 3:1 ratio every time. Post-16, we introduce dihybrid crosses, sex linkage and maybe autosomal linkage. There’s just one problem. Most of it just isn’t true in the real world of modern genetics. Little in nature behaves like that but it’s what was taught pre-war and it still hasn’t changed. Admittedly, modern GCSE specifications include references to DNA, protein synthesis and genetic engineering and A-level Biology has made progress, but the basics have not moved on. When I taught Mendelian genetics for all those years. I felt I was teaching mathematical logic rather than Biology. The pupils enjoyed solving problems because they could quickly understand the principles and apply them to novel examples. When exam time came round, they would get full marks because all the questions were basically the same. Work out the gametes, draw a Punnett square and there’s your answer. So why am I, like others over the past 15 years (Dougherty 2009; Radick 2023; Winterbottom 2016) so determined to see Mendelism removed if it’s guaranteeing examination success for my students? Firstly, most characters in the majority of organisms are not controlled by single genes but rather are polygenic, with many genes having a combined effect. Some genes are pleiotropic and many are multiallelic. I therefore feel that what we are teaching, while not a lie, is a rather peculiar example from a much bigger picture. Why is it taught like this? Radick believes that it was Bateson, who, in Mendel’s name, wanted biology and society reorganised around the recognition that heredity is destiny. Therefore, and more importantly, teaching Mendelism encourages some quite dangerous attitudes to genetics by the public. Most do not study Biology post-16, so they never get to see the bigger picture. They come to believe that ‘there’s a gene for’ every character, a concept that frequently appears in the press, and that environment plays little or no role. I believe it also encourages an acceptance of ‘Genetic Determinism”, an idea first proposed by Weissman and later made popular by Francis Galton in the early 20 century. It suggests that your fate is sealed at conception and your future is not in your hands but is simply determined by your genes. This is a very dangerous concept to be introducing to teenagers who should be allowed to feel that they are not slaves to their genomes and that humans are morally responsible agents. Galton, of course, is also associated with the term ‘nature versus nurture’ which implies that the two are somehow competing against each other. In reality, both genotype and environment contribute to the phenotype of so many characters so I suggest a better phrase would be ‘nature alongside nurture’. All teachers encounter pairs of ‘identical’ twins in their careers (I think I taught at least 10 pairs), so when discussing Twin Studies with teenagers, a useful tool in this topic, one should avoid saying things such as ‘isn’t it remarkable how similar monozygotic twins are’ but rather ‘isn’t it remarkable how different they are, considering they share the same genes’. This drives home the importance of minor changes in environment (nurture) in the determination of phenotypes. JOURNAL OF BIOLOGICAL EDUCATION 2023, VOL. 57, NO. 4, 707–708 https://doi.org/10.1080/00219266.2023.2243690