Evan Charney

Behavior genetics and postgenomics

The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. According to three widely held dogmas, DNA is the unchanging template of heredity, is identical in all the cells and tissues of the body, and is the sole agent of inheritance. Rather than being an unchanging template, DNA appears subject to a good deal of environmentally induced change. Instead of identical DNA in all the cells of the body, somatic mosaicism appears to be the normal human condition. And DNA can no longer be considered the sole agent of inheritance. We now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, epigenetic regulation, DNA variability, and somatic mosaicism appear to be particularly prevalent in the human brain and probably are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period and, in particular, in enabling phenotypic plasticity in offspring. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of minimal shared maternal effects, in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology.

Candidate Genes and Political Behavior

Political scientists are making increasing use of the methodologies of behavior genetics in an attempt to uncover whether or not political behavior is heritable, as well as the specific genotypes that might act as predisposing factors for—or predictors of—political “phenotypes.” Noteworthy among the latter are a series of candidate gene association studies in which researchers claim to have discovered one or two common genetic variants that predict such behaviors as voting and political orientation. We critically examine the candidate gene association study methodology by considering, as a representative example, the recent study by Fowler and Dawes according to which “two genes predict voter turnout.” In addition to demonstrating, on the basis of the data set employed by Fowler and Dawes, that two genes do not predict voter turnout, we consider a number of difficulties, both methodological and genetic, that beset the use of gene association studies, both candidate and genome-wide, in the social and behavioral sciences.

Political Liberalism, Deliberative Democracy, and the Public Sphere

Theorists of democracy emphasize the importance of a public sphere, distinct from the apparatus of the state, where citizens can freely associate, deliberate, and engage in collective will formation. Discourse ethicists and deliberative democrats locate the public sphere within civil society and the manifold associations that comprise it. For Seyla Benhabib, the public sphere is constituted by the anonymous “public conversation” of civil society. By contrast, John Rawls has a much more limited conception of the public sphere. For Rawls, public reason, which establishes norms for democratic discourse, applies to a limited domain. I defend Rawlss view against the charge that it depends upon an untenable distinction between the public and nonpublic spheres. I argue that Rawlss more limited “liberal” conception better guarantees the heterogeneity of associational life in civil society. I then argue that Rawls violates his own principles by partially collapsing the public-nonpublic distinction with potentially illiberal consequences.

Genopolitics and the Science of Genetics

In an earlier article we challenged the findings of Fowler and Dawes (FD) that two genes predict voter turnout as part of a more general critique of “genopolitics.” FD now acknowledge that their finding of a “significant” direct association between MAOA and voting was incorrect, but claim to have replicated their finding of an “indirect” association between 5HTT, self-reported church attendance, and self-reported voting. We show that this finding is likely driven by population stratification and omitted variable bias. We then explain why, from the standpoints of genetics, neuroscience, and evolutionary biology, genopolitics is a fundamentally misguided undertaking; we also respond to FDs charge that some of our previous statements concerning genetics are “highly misleading,” “extremely disingenuous,” and “even incorrect.” We show that their criticisms demonstrate a lack of awareness of some basic principles in genetics and of discoveries in molecular genetics over the past 50 years.

Politics, Genetics, and “Greedy Reductionism”

I would like to thank Alford, Funk, and Hibbing, and Hannagan and Hatemi, for agreeing to write critical responses to my article, and I am grateful for the opportunity afforded me to respond.

Political Science and Behavior Genetics

Political scientists have taken up behavior genetics (BG) at a momentous time in the science of genetics. Momentous, because the science of genetics is undergoing a paradigm shift [Petronis, A. (2010). Epigenetics as a unifying principle in the aetiology of complex traits and diseases. Nature, 465(7299), 721–727]. This shifting paradigm poses a significant challenge to both the prevailing methodologies of behavior genetics – twin, family, adoption studies – and one of the most noteworthy findings to emerge from such studies, that is, which we can call the principle of minimal parental effects. This is the supposition that the effect of the shared parental rearing environment on the behavioral phenotypes of offspring is statistically equivalent to zero (Plomin & Daniels, 1987). It is not uncommon nowadays to find twin, adoption, and family studies utilized in the study of political behavior (e.g., Alford, J., Funk, C. L., & Hibbing, J. R. (2005). Are political orientations genetically transmitted? American Political Science Review, 99(2), 153–167.); likewise, the principle of minimal parental effects is frequently invoked in such studies (e.g., Mondak, J. J., Hibbing, M. V., Canache, D., Seligson, M. A., & Anderson, M. A. (2010). Personality and civic engagement: An integrative framework for the study of trait effects on political behavior. American Political Science Review, 104(1), 85–110.). As we shall see, the challenge comes from recent discoveries in genetics that are radically transforming our understanding of the genome and its relationship to environment.

Author’s response: Humans, fruit flies, and automatons.

My response is divided into four sections: (1) is devoted to a potpourri of commentaries that are essentially in agreement with the substance of my target article (with one exception); in (2) I address, in response to one of the commentaries, several issues relating to the use of candidate gene association studies in behavior genetics (in particular those proposing a specific G × E interaction); in (3) I provide a detailed response to several defenses of the twin study methodology; and in (4) I conclude with several reflections on that methodology and the conception of human nature it has fostered.

Conservatives, liberals, and "the negative".

The authors connect conservatism with aversion to negativity via the tendentious use of the language of threats to characterize conservatism, but not liberalism. Their reliance upon an objective conception of the negative ignores the fact that much of the disagreement between liberals and conservatives is over whether or not one and the same state of affairs is negative or positive.

Cytoplasmic inheritance redux.

Since the early twentieth century, inheritance was seen as the inheritance of genes. Concurrent with the acceptance of the genetic theory of inheritance was the rejection of the idea that the cytoplasm of the oocyte could also play a role in inheritance and a corresponding devaluation of embryology as a discipline critical for understanding human development. Development, and variation in development, came to be viewed solely as matters of genetic inheritance and genetic variation. We now know that inheritance is a matter of both genetic and cytoplasmic inheritance. A growing awareness of the centrality of the cytoplasm in explaining both human development and phenotypic variation has been promoted by two contemporaneous developments: the continuing elaboration of the molecular mechanisms of epigenetics and the global rise of artificial reproductive technologies. I review recent developments in the ongoing elaboration of the role of the cytoplasm in human inheritance and development.

Restoring the Lost Constitution: The Presumption of Liberty and Libertarianism Without Inequality

RANDY BARNETT IS AMONG the world’s leading libertarian academics and lawyers, perhaps second only to Richard Epstein in influence. In fact, Mr. Barnett (1977, p. 15) has defended anarcho-capitalism in these very pages, which makes his most recent book, Restoring the Lost Constitution, most curious. In it, he attempts to legitimate the United States government by arguing that, properly understood, the U.S. Constitution establishes libertarianism throughout the land by both limiting the federal government’s powers and empowering the federal government to restrain the states. Though well-intentioned, the book is fatally flawed. Mr. Barnett’s arguments that a monopoly government can be legitimate are unpersuasive; his arguments that the federal government should limit its own power are futile; and his arguments that the federal government should impose libertarianism on the states are dangerous.