Epigenetics and Allostasis

• DOI: 10.1177/0734016814530148
• Date: 01 December 2014
• Published date: 01 December 2014
• Author: Ilhong Yun,Anthony Walsh
• Subject Matter: Articles

Article
Criminal Justice Review
2014, Vol. 39(4) 411-431
Epigenetics and Allostasis:
ª 2014 Georgia State University
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DOI: 10.1177/0734016814530148
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Anthony Walsh1 and Ilhong Yun2
Abstract
The purpose of this review article is to show how sociological theories of criminal behavior can be
illuminated by drawing on insights from epigenetics and the concept of allostasis. The burgeoning
field of epigenetics has the promise of burying whatever lingering fears about ‘ genetic determinism’’
some criminologists may still have. Epigenetics concerns itself with environmental conditions that
regulate the transcript and expression of genes and is a discipline that can be of enormous use to
criminology because it emphasizes the plasticity of the human genome. We know that the brain is
amazingly plastic and a major target for epigenetic modification. All stimuli must be funneled to the
brain before a behavioral response is initiated. Because the brain and the systems of stress
response—the hypothalamic–pituitary–adrenal (HPA) axis and the autonomic nervous system
(ANS)—are designed for plasticity, they are highly vulnerable to epigenetic and allostatic changes
when exposed to environmental experiences that are evolutionarily novel. The downregulation of
systems of behavioral control (dopamine/serotonin ratios and hyporeactive HPA axis and ANS) has
frequently and strongly shown to be related to criminal behavior. This article outlines how these
changes occur, and why they occur most frequently in deprived environments. We believe that an
understanding of how criminogenic environments ‘‘get into’’ the person molecularly can plug gaps in
poverty- and control-based theories of criminal behavior. We present this article in the spirit of
biosocial criminology which avers that the more we come to understand and appreciate the biology
of behavior, the more we realize the importance of the environment.
Keywords
epigenetics, allostasis, experience dependent, BAS/BISs, nurturing, teratogens
Introduction
‘‘The more we know about the genetics of behavior, the more important the environment appears to
be’’ (Baker, Bezdjian, & Raine, 2006, p. 44). This truism, shared by geneticists and biosocial crim-
inologists, affirms the constant two-way dance between the genome and its environment: The effects
of the environment depend on genetics and the effects of genetics depend on the environment.
1 Department of Criminal Justice, Boise State University, Boise, ID, USA
2 Department of Police Administration, Chosun University, Gwangju, South Korea
Corresponding Author:
Ilhong Yun, Department of Police Administration, Chosun University, Gwangju, South Korea.
Email: yun.ilhong@gmail.com

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Criminal Justice Review 39(4)
Despite the fidelity with which DNA replicates itself, the genome is subject to nonmutational
changes initiated by environmental experiences. This review article hopes to demonstrate how
genome-changing processes illuminate traditional sociological theories of crime. We do so by high-
lighting how these processes impact, or are impacted by, variables emphasized in these theories,
such as poverty, abuse and neglect, self-control, IQ, and drug and alcohol abuse.
The biosocial processes involved are epigenetics and allostasis. Epigenetics is any process
that alters gene expression without altering the DNA sequence (Weinhold, 2006). Allostasis
is a process that restores a physiological system to homeostasis by changing its set points
(McEwen & Wingfield, 2003). Epigenetic and allostatic processes are biological processes that
are initiated by environmental events. Epigenetics and allostasis are thus sites where nature
meets nurture and where environments penetrate humans at the cellular level. As Michael
Meaney put it, because of the discovery of these processes: ‘‘We’re beginning to draw
cause-and-effect arrows between social and economic macrovariables down to the level of the
child’s brain’’ (in Watters, 2006, p. 75).
We wish to emphasize three initial points, so that our intent in this review is not misconstrued.
First, we are not attempting to show how epigenetic and allostatic data can be integrated into current
criminological empirical studies; these kinds of data are extremely hard to come by. Rather, we offer
this article in the spirit of Douglas Massey’s plea to incorporate these processes into our thinking for
a more nuanced understanding of how adverse environments impact those unfortunate enough to
experience them. Massey (2004, p. 22) asserts that:
By understanding and modeling the interaction between social structure and allostasis, social scientists
should be able to discredit explanations of racial differences in terms of pure heredity. In an era when
scientific understanding is advancing rapidly through interdisciplinary efforts, social scientists in gen-
eral—and sociologists in particular—must abandon the hostility to biological science and incorporate its
knowledge and understanding into their work.
Second, we are limiting our discussion to the earliest years of life when the brain is most plastic (i.e.,
most responsive to calibration by the environment). Early experiences organize the infant brain and
place it on a trajectory it may find difficult to change. This does not imply that it is impossible to
change. We are only asserting that early environmental experiences may foster epigenetic and allo-
static alterations to the organism’s genome and brain which may result in a hostile attribution style
that induce it to engage in antisocial behavior in later life. This is analogous to Glen Walters’ ‘‘four
Cs’’ in his lifestyle theory (1990) of criminal behavior. Walters posits that initial conditions (genet-
ics and developmental experiences) lead to behavioral choices, which in turn lead to cognition
(one’s style of thinking) and on to criminal behavior.
Third, by emphasizing early family experiences, we are in no way ignoring behavioral genetic
studies showing that the shared environment has weak to zero effects on variance in cognitive,
personality, and behavioral outcomes (e.g., Boutwell & Beaver, 2010). This is not the same as saying
that shared environment has no effect on the mean level of these variables. The inference that shared
family environment matters very little because it accounts for little variance on a trait or behavior is
wrong (Rutter, 2012). Heritability can remain stable even while the mean level of a variable is rising
or falling. Under the influence of learning within the family in a population, the mean strength of a
given variable can be raised or lowered while the population variance—the basis of computing her-
itability—remains unaffected. In any case, epigenetic and allostatic processes are by definition pro-
cesses that engage the nonshared environment because the effects of experiences such as abuse and
neglect or exposure to teratogenic substances will not be uniform across all individuals experiencing
them; there is a great deal of heterogeneity of responses to all kinds of environmental adversity
(McEwen & Gianaros, 2010).

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Walsh and Yun
413
Neurological and Genomic Plasticity
Whether we welcome or reject biology’s increasing presence in criminology, presumably we are all
Darwinists. The fact that our most readily observed adaptations (upright posture, opposable thumbs,
speech, empathy, etc.) evolved many hundreds of thousands of years ago does not mean that the
human genome is fixed and inflexible. The genome is designed to adapt to conditions existing in
each individual’s lifetime as well as the conditions existing throughout the vast expanse of the spe-
cies’ evolution (Landecker & Panofsky, 2013). The DNA sequences that provide the instructions for
building proteins do not change in a person’s lifetime, but the regulatory processes that control gene
transcription and expression change in response to experience. Gottesman and Hansen (2005, p. 265)
ask ‘‘To what are these genetic adaptation responding?’’ and reply that ‘‘The obvious answer is the
environment.’’ Genes are at the beck and call of their carriers, constantly responding to their needs
by making the hormones, neurotransmitter, and cell structure proteins needed to meet environmental
challenges.
Before looking at how the environment changes gene expression, a digression into the process of
brain ‘‘softwiring’’ by environmental experience is warranted because this processes is well estab-
lished and provides analogies with epigenetic and allostatic processes. About 70% of human genes
are expressed in the brain (Chiao & Ambady, 2007) and brain chemistry (neurotransmitters, recep-
tors, transporters, and enzymes) is the primary target for epigenetic changes that lead to (or exacer-
bate existing) patterns of traits and behaviors of interest to criminologists (Walsh & Bolen, 2012).
Just as the species genome physically captures the environment in evolutionary time by selecting
genetic variants that fit organisms to it, the brain physically captures environmental events that fit
people into the current environment via experience-dependent (ED) processes (Schon & Silven,
2007). ED developmental processes reflect the brain’s ability to calibrate itself to the environment
and are distinguished from experience-expected (EE) mechanisms that are hardwired and reflect
the phylogenic history of the brain. All members of a species inherit species-typical brain structures
and functioning produced by a common pool of genetic...