Linkage before Mendelism? Plant-breeding research in Central Europe, c.1880–1910
The concept of a “map” based on linkage patterns, as developed by the Morgan school from 1913, is another instance of the scientist imposing a particular conceptual meaning upon longstanding observations. For as I will show here, it was well known among nineteenth-century plant-breeders (as by animalbreeders earlier) that particular traits were usually inherited together (known as “correlations”), though occasional deviations from the pattern were also recognized. Significantly, the breeders were not simple empiricists interested only in useable rules of thumb, for they too advanced explanations for correlated traits, albeit of a very unMendelian kind. Comparing late nineteenth-century breeders’ explanations of correlation with those advanced by early Mendelians suggests that the rediscovery of Mendelism was accompanied, at least in some quarters, by a fundamental shift in the underlying vision of the organism.