Lamarckian Inheritance

Lamarckian inheritance is the thesis that organisms can pass on characteristics acquired during their lifetime to their offspring — that use and disuse of organs, or environmentally induced changes, can be directly inherited. This model of heredity, most associated with Jean-Baptiste Lamarck, was largely displaced by the Modern Synthesis of Mendelian genetics and Darwinian selection, which treats variation as random with respect to fitness and inheritance as digital rather than analog. Yet the concept has refused to die: genetic assimilation provides a Darwinian mechanism for Lamarckian-looking outcomes, and recent work on epigenetic inheritance has revived interest in whether acquired traits can be transmitted through molecular mechanisms that do not alter DNA sequence. The question is not whether Lamarck was right — he was not — but whether his error contained a structural insight about the relationship between development and heredity that the Modern Synthesis was too quick to discard.