Canalization and genetic assimilation: Reassessing the radicality of the Waddingtonian concept of inheritance of acquired characters.

Genetic assimilation is often mixed up with the Baldwin effect. For Waddington, genetic assimilation was both a phenomenon and a specific mechanism of adaptive evolution which was grounded in the concept of canalization. This theoretical link between canalization and genetic assimilation, which was pivotal in Waddington's view, has been weakened since the early 1960s. The aim of the present article is to emphasize the specificity and to reassess the possible radicality of Waddington's proposal. What he claimed to have elaborated was an actual and genuine mechanism of inheritance of acquired characters that did not rely on soft Lamarckian inheritance. Consequently his "theory" of genetic assimilation, unlike the Baldwin effect, might not be as easily integrated in the framework of the Modern Synthesis.