Comment on "Epigenetics and the renaissance of heresy"

Abstract

Lamarckian inheritance (i.e., inheritance of acquired character) and Richard Golschmidt's concept of "systemic mutations" and their role in macroevolution have been two of the most controversial topics in the history of evolutionary biology. The concept of Lamarckian inheritance was put to rest first by Weismann's germplasm theory and experiment and later by the discovery of Mendelian inheritance. Goldschmidt's theory of macroevolution by systemic mutations was put to rest by the discovery of DNA's structure and subsequent demonstration showing allelic variation as the basis for genetic and phenotypic differences observed among organisms. Some authors are using recent demonstrations of epigenetic inheritance in higher organisms to support Lamarckian inheritance and Golschmidt's theory of macroevolution by systemic mutations. In this paper, I show that the recent discoveries related to mutations, such as the so called "directed" mutations in bacteria, and epigenetic inheritance in higher organisms are basically an extension of the notion of "mutation" and thus of the concept of "heritable variation" required for evolution. While the new discoveries of the laws of developmental transformations are enriching our knowledge of the intricate relationship between genotype and phenotype, the findings of epigenetic inheritance do not challenge the basic tenets of the neo-Darwinian theory of evolution, as other than producing new variation no new processes of evolutionary change have been added to the ones we already know — mutation, migration, selection, and drift.Key words: neo-Darwinian theory of evolution, epigenetics, Lamarckian inheritance, systemic mutations, speciation, macroevolution.