May 18, 2009

Review article on epigenetic inheritance

From the paper:
Incorporating epigenetic inheritance into evolutionary theory extends the scope of evolutionary thinking and leads to notions of heredity and evolution that incorporate development. Dobzhansky's definition of evolution as “a change in the genetic composition of populations” (1937, p.11) appears to be too narrow because it does not incorporate all sources of heritable variations. Both evolution and heredity need to be redefined. Jablonka and Lamb (2007a,b,c) suggested that evolution should be redefined as the set of processes that lead to changes in the nature and frequency of heritable types in a population, and heredity as the developmental reconstruction processes that link ancestors and descendants and lead to similarity between them. These deliberately broad redefinitions allow evolutionary possibilities denied by the “Modern Synthesis” version of evolutionary theory, which states that variations are blind, are genetic (nucleic acid‐based), and that saltational events do not significantly contribute to evolutionary change (Mayr 1982). The epigenetic perspective challenges all these assumptions, and it seems that a new extended theory, informed by developmental studies and epigenetic inheritance, and incorporating Darwinian, Lamarckian, and saltational frameworks, is going to replace the Modern Synthesis version of evolution (Jablonka and Lamb 2005, 2007c). We believe, therefore, that the impact of epigenetics and epigenetic inheritance on evolutionary theory and the philosophy of biology will be profound.
Some related posts:

The Quarterly Review of Biology, June 2009, vol. 84, no. 2, DOI: 10.1086/598822


Eva Jablonka, Gal Raz


This review describes new developments in the study of transgenerational epigenetic inheritance, a component of epigenetics. We start by examining the basic concepts of the field and the mechanisms that underlie epigenetic inheritance. We present a comprehensive review of transgenerational cellular epigenetic inheritance among different taxa in the form of a table, and discuss the data contained therein. The analysis of these data shows that epigenetic inheritance is ubiquitous and suggests lines of research that go beyond present approaches to the subject. We conclude by exploring some of the consequences of epigenetic inheritance for the study of evolution, while also pointing to the importance of recognizing and understanding epigenetic inheritance for practical and theoretical issues in biology.



terryt said...

The most amazing thing about this is that Lamark may have been basically correct after all.

Maju said...

I would not go that far: fundamental evolution still seems to happen through genetic changes. What epigenetics seems to do is to fine-tune that basic genetic frame into variable derived forms, which can be inherited even for several generations but do not directly alter the genetic structure (so are in fact reversible probably).

It is very posible though that some phenotypic traits are defined by epigenetic semi-inheritable modifications as much as by genes.

At least that is what I understand.

DavidB said...

Eva Jablonka is a single-issue bore who has been playing the same record for about 20 years. It's a bit like D. S. Wilson and group selection - these people seem to think if they keep repeating themselves for long enough they will wear down the opposition. Unfortunately, they may be right.

Emil Nilsson said...

This "epigenetic inheritance" reminds me of Darwins pangeneses hypotheses ( Darwins problem was that if information was sent from the various cells of the body to the germcells, how come that parents who lost their arms do not give birth to one-armed babies? Or just think about the cultural practice involving the private parts of little boys...

Inherited epigenetic modifications must be passed on through the germline. That leaves just a little space for environment based modification of gene expression status, like methylation of DNA. This is far from both Lamarck and Darwins pengeneses. Or do somebody think its even possible with signals from the somatic cells affecting the germcells? I do not think so.