Historically speaking, I'm not sure, but I'd imagine the same debate would be had there too. This isn't just an epistemological question, but the product of multiple scientific revolutions (the return of atomism in the late 19C, quantum mechanics, neurophysiology, cybernetics...), so, to take a Kuhnian position, the innovations of the 1950s especially are well within the same epistemological regime.

Mendel already showed the discreteness of genes, without knowing the structure of DNA, in the 1860s. And I believe Darwin, though not aware of Mendel's work, realised that continuous genes would be a problem for his theory.