How is Epigenetics Different from Genetics?

by Shea Robison

Epigenetics is an emerging field of research related to, but in many ways distinct from, genetics.  While the basic premises of genetics are widely known and accepted, what is much less well-known is that there are biological processes ‘above’ the genome called collectively the epigenome (from the Greek root epi-, meaning ‘above’ or ‘over’).  These processes regulate the expression of genes in the genome in response to influences in the immediate environment, though without modifications of the DNA.  Epigenetics is thus the study of epigenomic modifications of genetic expression.  What is also not well-known is that some of these epigenetic changes in genetic expression can also be passed on to multiple generations, which is a fundamental challenge to many of the most basic tenets of genetics.  As genetics is already such a significant influence on policy, the challenges to genetics represented by the emerging knowledge from epigenetics constitute a significant challenge to conventional policy prescriptions as well.

Epigenetics is just one aspect of what is being called the Extended Synthesis of evolutionary biology,[1] in distinction to what is referred to as the Modern Synthesis of evolutionary biology, or the combination of the Mendelian view of genetics with Darwinian evolution which coalesced during the first half of the 20th century.[2]  Since this time, there have been remarkable advances in technology and in our understanding of the processes involved in biological development and evolution.  Contemporary epigenetics is a product of these recent advances, but the basic concepts of epigenetics have a long history of their own, some of which predate major components of the Modern Synthesis.

The Modern Synthesis presented fundamental challenges to traditional conceptions about human origins and our relationship to each other and to our environments. These challenges to conventional thought gradually worked their way into new approaches to public policies, primarily through the novel causal narratives generated by the Modern Synthesis.  The results emerging from epigenetics likewise challenge many of the foundational assumptions of both conventional Western thought as well as the Modern Synthesis itself in many unique ways.  Just as the narratives of genetics now influence public policies in distinct ways, so also will the emerging narratives of epigenetics introduce unanticipated changes in public policies.

The Modern Synthesis

The term ‘Modern Synthesis’ was brought to prominence by Julian Huxley in his book Evolution: The Modern Synthesis published in 1943,[3] but primary credit for this particular integration of evolution and genetics is often given to four seminal figures and the books they wrote between 1937 and 1950 (all of which – not coincidentally – were published by the Columbia University Press) – Theodosius Dobzhansky and his Genetics and the Origin of Species,[4] Ernst Mayr and his Systematics and the Origin of Species,[5] G.G. Simpson and his Tempo and Mode in Evolution,[6] and George Stebbins and his Variation and Evolution in Plants.[7]  These books were noteworthy for the different ways these authors “molded Darwin’s evolution by natural selection within the framework of rapidly advancing genetic knowledge.”[8]  Many other scientists during this time were also integrating ideas from different areas of research that challenged the traditional understanding of evolution that had been prevalent since the publication of Charles Darwin’s On the Origin of the Species in 1859.  The result of this integration was the scientific consensus of evolution as a gene-centered process which came to be called the Modern Synthesis.  In fact, this movement is called the Modern Synthesis because until the synthesizing work of Dobzhansky and the others, Mendelian genetics and Darwinian evolution were actually competing and seemingly irreconcilable paradigms.[9]

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[1] Pigliucci, M. & Muller, G. (2010). Evolution: The Extended Synthesis. Cambridge, Mass.: MIT Press.

[2] Mayr, E. (1980). The Evolutionary synthesis: perspectives on the unification of biology. Cambridge, Mass.: Harvard University Press.

[3] Huxley, J. (1943). Evolution: the modern synthesis. New York: Harper & Brothers.

[4] Dobzhansky, T. (1937). Genetics and the origin of species. New York: Columbia University Press.

[5] Mayr, E. (1942). Systematics and the origin of species. New York: Columbia University Press.

[6] Simpson, G. G. (1944). Tempo and mode in evolution. New York: Columbia Univ. Press.

[7] Stebbins, G. L. (1950). Variation and evolution in plants. New York: Columbia University Press.

[8] Callebaut, W. (2010). The Dialectics of Dis/Unity in the Evolutionary Synthesis and its Extensions. In Evolution: The Extended Synthesis (eds. M. Pigliucci and G. Muller). Cambridge: The MIT Press.

[9] Burian, R. (2005). The Epistemology of Development, Evolution, and Genetics. Cambridge: Cambridge University Press. See also Bowler, P. J. (1983). The Eclipse of Darwinism. Baltimore: The Johns Hopkins University Press; Bowler, P. J. (1988). The Non-Darwinian Revolution. Baltimore, MD: Johns Hopkins University Press; Bowler, P. J. (1989). The Mendelian Revolution. Baltimore, MD: Johns Hopkins University Press; Depew, D. J., and B. H. Weber (1995). Darwinism Evolving : Systems Dynamics and the Genealogy of Natural Selection. Cambridge, MA: MIT Press; Gayon, J. (1998). Darwinism’s Struggle for Survival: Heredity and the Hypothesis of Natural Selection. Translated by M. Cobb. Cambridge: Cambridge University Press; Provine, W. B. (1971). The Origins of Theoretical Population Genetics. Chicago: Chicago University Press.

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