the social brain meets the reactive genome neuroscience, epigenetics and the new social biology

frontiersin |  The rise of molecular epigenetics over the last few years promises to bring the discourse about the sociality and susceptibility to environmental influences of the brain to an entirely new level. Epigenetics deals with molecular mechanisms such as gene expression, which may embed in the organism “memories” of social experiences and environmental exposures. These changes in gene expression may be transmitted across generations without changes in the DNA sequence. Epigenetics is the most advanced example of the new postgenomic and context-dependent view of the gene that is making its way into contemporary biology. In my article I will use the current emergence of epigenetics and its link with neuroscience research as an example of the new, and in a way unprecedented, sociality of contemporary biology. After a review of the most important developments of epigenetic research, and some of its links with neuroscience, in the second part I reflect on the novel challenges that epigenetics presents for the social sciences for a re-conceptualization of the link between the biological and the social in a postgenomic age. Although epigenetics remains a contested, hyped, and often uncritical terrain, I claim that especially when conceptualized in broader non-genecentric frameworks, it has a genuine potential to reformulate the ossified biology/society debate.

Profound conceptual novelties have interested the life-sciences in the last three decades. In several disciplines, from neuroscience to genetics, we have witnessed a growing (and parallel) crisis of models that tended to sever biological factors from social/environmental ones. This possibility of disentangling neatly what seemed to belong to the “biological” from the “environmental” and to attribute a sort of causal primacy to biological factors (equated with genetic) in opposition to social or cultural ones (thought of as being more superficial, or appearing later in the ontology of development) was part and parcel of very vocal research-programs in the 1990s. These programs were all more or less heirs of the gene-centrism of sociobiology: from evolutionary psychology, to a powerful nativism that was very influential in psychology and cognitive neuroscience with its obsessive emphasis on hardwiring culture or morality into the brain.

These programs have always received a barrage of criticisms from several intellectual traditions (Griffiths, 2009; Meloni, 2013a), particularly those with roots in ethology (Lehrman, 1953, 1970; Bateson, 1991; Bateson and Martin, 1999), and developmental biology (West and King, 1987; Griffiths and Gray, 1994; Gottlieb, 1997; Oyama, 2000a[1985],b; Oyama et al., 2001; Griffiths, 2002; Moore, 2003). However, never as in this last decade, we have had scientific evidence that the dichotomous view of biology vs. society and biology vs. culture is biologically fallacious (Meaney, 2001a).

Paradoxically, it was exactly the completion of the Human Genome Project that showed that the view of the gene as a discrete and autonomous agent powerfully leading traits and developmental processes is more of a fantasy than actually being founded on scientific evidence, as highlighted by the “missing heritability” case (Maher, 2008). The image of a distinct, particulate gene marked by “clearly defined boundaries” and performing just one job, i.e., coding for proteins, has been overturned in recent years (Griffiths and Stotz, 2013: 68; see also Barnes and Dupré, 2008; Keller, 2011). Although discussions are far from being settled, the work of the ENCODE consortium for instance has been crucial in showing the important regulatory functions of what, in a narrow “gene-centric view”, was supposed to be mere “junk DNA” (Encode, 2007, 2012; Pennisi, 2012). Not only does a very small percentage of the genome (less than 2%) act according to the classical definition of the gene as a protein-coding sequence, but most of the non-protein coding DNA in fact plays an important regulatory function. The genome is therefore today best described as a “vast reactive system” (Keller, 2011) embedded in a complex regulatory network with distributed specificity (Griffiths and Stotz, 2013). An important part of this regulatory network is involved in responding to environmental signals, which can cover a very broad range of phenomena, from the cellular environment around the DNA, to the entire organism and, in the case of human beings, their social and cultural dynamics.

To sum up a decade of empirical and conceptual novelties the conceptualization of the gene has become dynamic and “perspectival” (Moss, 2003), in what can be called the new “postgenomic view¹”; it addresses genes as part of a broader regulative context, “embedded inside cells and their complex chemical environments” that are, in turn, embedded in organs, systems and societies (Lewkowicz, 2010). Genes are now seen as “catalysts” more than “codes” in development (Elman et al., 1996), “followers” rather than “leaders” in evolution (West-Eberhard, 2003; Robert, 2004). The more genetic research has gone forward, the more genomes are seen to “respond in a flexible manner to signals from a massive regulatory architecture that is, increasingly, the real focus of research in ‘genetics’” (Griffiths and Stotz, 2013: 2; see also Barnes and Dupré, 2008; Dupré, 2012).

As Michael Meaney (2001a: 52, 58) wrote more than a decade ago: “There are no genetic factors that can be studied independently of the environment, and there are no environmental factors that function independently of the genome… . At no point in life is the operation of the genome independent of the context in which it functions.” Moreover, “environmental events occurring at a later stage of development … can alter a developmental trajectory” making meaningless any linear regression studies of nature and nurture. Genes are always “genes in context”, “context-dependent catalysts of cellular changes, rather “controllers” of developmental progress and direction” (Nijhout, 1990: 444), susceptible to be reversed in their expression by individual’s experiences during development (Champagne and Mashoodh, 2009).