We’ve been misled. We’re taught that Gregor Mendel’s pea-crossing experiments provide a timelessly excellent foundation for genetics. Yet in the early twentieth century those experiments were heavily criticized for neglecting the role of environments in shaping hereditary characters. But, as Gregory Radick shows, those criticisms failed to carry the day – not because they were defeated in reasoned, evidence-based debate, but because of mere historical accident. As a result, the mistaken idea that genes determine character traits was allowed to persist.

In the year 1900, biology finally caught up with Gregor Mendel. Back in 1865, Mendel had reported the results of crossbreeding experiments done in the garden of his monastery in Brünn (now Brno, in Czechia). Working at unprecedented scale and taking painstaking care, he crossed yellow-seeded pea plants with green-seeded ones, round-seeded varieties with wrinkled-seeded ones, and so on, tracking seven binary character pairs in multiple combinations through several generations. To explain the patterns he found, Mendel offered a brilliant hypothesis: underlying the visible characters are invisible factors which, like the characters themselves, don’t blend into each other but retain their original identities.

Yet far from celebrating this discovery of the gene – heredity’s fundamental particle – Mendel’s contemporaries responded with polite yawns, and he died in 1884 in relative obscurity. Sixteen years later, however, three European botanists independently rediscovered his patterns and explanations, bringing belated recognition to Mendel and soon launching the modern science of heredity, first known as “Mendelism,” then as “genetics.”

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If all you know about the early history of genetics is the textbook rendition of it, you’ll have little motive for querying the Mendelian framing

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