Locating Lewontin on the genotype–phenotype map

Over the last century, evolutionary genetics has steadily advanced our understanding of the architecture of simple and complex traits of individuals among diverse organisms. In this context, Tautz et al. (2026), in their Perspective “Beyond Mendel: a call to revisit the genotype–phenotype map through new experimental paradigms,” call for genetics to move beyond one-gene-one-trait thinking toward developing experimental approaches to embrace pleiotropy, epistasis, and context-dependent complexity in the genotype–phenotype (G–P) map. They emphasize the limits of what they believe are conventional approaches to genetic analyses, including missing heritability. We were struck by the absence of any mention of Lewontin's (1974a) G–P map concept in Tautz et al.'s Perspective. Lewontin's scheme represents interconnections among multilocus genotype, development, and phenotype. This omission may be accidental, but it points to a persistent divide among population, quantitative, and molecular genetics. That gap motivates our aim in this letter: to show how three of Lewontin's ideas complement those of Tautz et al.: units of selection, norms of reaction, multilocus interactions and genome complexity.