Goings on in Mendel’s Garden

Gregor Mendel gave us the tools by which to do modern genetics, and we have a century of progress to show for it. We properly credit Mendel and his peas for showing us the particulate nature of inheritance, but his work both enabled and disabled evolutionary thinking for several decades after its rediscovery. Since the factors he studied didn’t change over generations, Mendel’s discoveries solved the problem that perplexed Darwin, that blending inheritance would swamp variation and prevent evolution from happening. Yet, for the same reason, Mendel’s work impeded evolutionary thought because evolution requires change, and discrete variation was also incompatible with darwinian gradualism. Eventually things were worked out, we got our unified theory (the neodarwinian Synthesis), and it rested on Mendel’s discoveries. Despite his contributions, there has long been a bit of queasiness about Mendel. Almost as soon as his work was discovered in 1900, persistent suggestion arose that the honorable Moravian monk had falsified his data. A recent analysis of these allegations has helped illuminate the issues, and they fall entirely to Mendel’s credit. This vindication is good for Mendel’s reputation, and his principles are invoked routinely when inheritance is discussed. But this may have inadvertently led us astray, in ways for which we are paying a price today. The artificial nature of his experiments lured us into confusing the inheritance of traits with the inheritance of genes. And this in turn has led to an unwarranted phenogenetic (see Note 1) determinism that impairs our understanding of biology.