Human Behavior Genetics Research Articles

Behavior genetics and randomized controlled trials: A misleading analogy.

Madole & Harden argue that just as the results of randomized controlled trials (RCTs) represent gains in causal knowledge and are useful, despite their limitations, so too are the findings of human behavior genetics. We argue that this analogy is misleading. Unlike RCTs, the results of human behavior genetics research cannot suggest efficacious interventions, nor point toward future research.

A Century of Behavioral Genetics at the University of Minnesota.

The University of Minnesota has played an important role in the resurgence and eventual mainstreaming of human behavioral genetics in psychology and psychiatry. We describe this history in the context of three major movements in behavioral genetics: (1) radical eugenics in the early 20th century, (2) resurgence of human behavioral genetics in the 1960s, largely using twin and adoption designs to obtain more precise estimates of genetic and environmental influences on individual differences in behavior; and (3) use of measured genotypes to understand behavior. University of Minnesota scientists made significant contributions especially in (2) and (3) in the domains of cognitive ability, drug abuse and mental health, and endophenotypes. These contributions are illustrated through a historical perspective of major figures and events in behavioral genetics.

The Genetics of Human Behavior

The Genetics of Human Behavior

CyberGenomics: Application of Behavioral Genetics in Cybersecurity.

Cybersecurity (CS) is a contemporary field for research and applied study of a range of aspects from across multiple disciplines. A cybersecurity expert has an in-depth knowledge of technology but is often also recognized for the ability to view technology in a non-standard way. This paper explores how CS specialists are both a combination of professional computing-based skills and genetically encoded traits. Almost every human behavioral trait is a result of many genome variants in action altogether with environmental factors. The review focuses on contextualizing the behavior genetics aspects in the application of cybersecurity. It reconsiders methods that help to identify aspects of human behavior from the genetic information. And stress is an illustrative factor to start the discussion within the community on what methodology should be used in an ethical way to approach those questions. CS positions are considered stressful due to the complexity of the domain and the social impact it can have in cases of failure. An individual risk profile could be created combining known genome variants linked to a trait of particular behavior using a special biostatistical approach such as a polygenic score. These revised advancements bring challenging possibilities in the applications of human behavior genetics and CS.

Twin studies to GWAS: there and back again.

The field of human behavioral genetics has come full circle. It began by using twin/family studies to estimate the relative importance of genetic and environmental influences. As large-scale genotyping became cost-effective, genome-wide association studies (GWASs) yielded insights about the nature of genetic influences and new methods that use GWAS data to estimate heritability and genetic correlations invigorated the field. Yet these newer GWAS methods have not replaced twin/family studies. In this review, we discuss the strengths and weaknesses of the two approaches with respect to characterizing genetic and environmental influences, measurement of behavioral phenotypes, and evaluation of causal models, with a particular focus on cognitive neuroscience. This discussion highlights how twin/family studies and GWAS complement and mutually reinforce one another.

Causal Reasoning About Human Behavior Genetics: Synthesis and Future Directions.

When explaining the causes of human behavior, genes are often given a special status. They are thought to relate to an intrinsic human 'essence', and essentialist biases have been shown to skew the way in which causation is assessed. Causal reasoning in general is subject to other pre-existing biases, including beliefs about normativity and morality. In this synthesis we show how factors which influence causal reasoning can be mapped to a framework of genetic essentialism, which reveals both the shared and unique factors underpinning biases in causal reasoning and genetic essentialism. This comparison identifies overlooked areas of research which could provide fruitful investigation, such as whether normative assessments of behaviors influence the way that genetic causes are ascribed or endorsed. We also outline the importance of distinguishing reasoning processes regarding genetic causal influences on one's self versus others, as different cognitive processes and biases are likely to be at play.

Insilico Analysis of Inhibitors Related to Aggressive Behavior in Human Beings

Studies of human behavioral genetics have made it easier to understand the relative contributions of genetics and the environment in observed variation in human behavior. The genes responsible for the aggressive behavior with the help of literary works along with the proteins they code were identified and the functions of these proteins and the pathways in which they are involved are also identified. According to the functions of these receptors it is observed that over expression of 2 main receptors lead to abnormal and increased aggression. This means inhibiting this over expression would be a source of solution to reduce this abnormal behavior. Therefore ligands are selected from GeneCards and Malacards based on their inhibiting properties which can act as antipsychotic agents, dopamine antagonists, serotonin antagonist and antidepressants. These ligands are then screened based on the ADMET properties. The results show that ligands such as L-tyrosine, dexmethylphenidate, olanzapine, parozetine, selegiline and loxapine are more favorable to bind with the proteins. These ligands are then docked with the receptors to find the appropriate inhibitors. The interaction between the receptors and the ligands are studied, the docking study reveals that the appropriate ligands can be used as a solution for aggressive, criminal and violent behavioral changes as it helps to retain the normal behavior.

子どもによる親への対人的信頼感 : 児童・思春期の双生児を対象とした人間行動遺伝学的検討

子どもによる親への対人的信頼感 : 児童・思春期の双生児を対象とした人間行動遺伝学的検討

The heritability fallacy.

The term 'heritability,' as it is used today in human behavioral genetics, is one of the most misleading in the history of science. Contrary to popular belief, the measurable heritability of a trait does not tell us how 'genetically inheritable' that trait is. Further, it does not inform us about what causes a trait, the relative influence of genes in the development of a trait, or the relative influence of the environment in the development of a trait. Because we already know that genetic factors have significant influence on the development of all human traits, measures of heritability are of little value, except in very rare cases. We, therefore, suggest that continued use of the term does enormous damage to the public understanding of how human beings develop their individual traits and identities. WIREs Cogn Sci 2017, 8:e1400. doi: 10.1002/wcs.1400 For further resources related to this article, please visit the WIREs website.

Benson Earl Ginsburg (1918–2016): a pioneer in behavior genetics

Benson Earl Ginsburg (1918–2016): a pioneer in behavior genetics

Genetic Prediction.

The fundamental reason that the genetics of behavior has remained so controversial for so long is that the layer of theory between data and their interpretation is thicker and more opaque than in more established areas of science. The finding that variations in tiny snippets of DNA have small but detectable relations to variation in behavior surprises no one, at least no one who was paying attention to the twin studies. How such snippets of DNA are related to differences in behavior-known as the gene-to-behavior pathway-is the great theoretical problem of modern behavioral genetics. Given that intentional human breeding is a horrific prospect, what kind of technology might we want (or fear) out of human behavioral genetics? One possibility is a technology that could predict important behavioral characteristics of humans based on their genomes alone. A moment's thought suggests significant benefits and risks that might be associated with such a possibility, but for the moment, just consider how convincing it would be if on the day of a baby's birth we could make meaningful predictions about whether he or she would become a concert pianist or an alcoholic. This article will consider where we are right now as regards that possibility, using human height and intelligence as the primary examples.

Genetic basis of executive functions: Findings from human behavioral genetics and genetic polymorphism research

Genetic basis of executive functions: Findings from human behavioral genetics and genetic polymorphism research

Introduction to the Special Issue: The Interplay Between Genetic Factors and the Peer Environment in Explaining Children's Social Adjustment

Virtually all aspects of human development are subject to both genetic (i.e., heritable) and environmental influences that conjointly shape developmental outcomes through various mechanisms of gene-environment interplay. This special issue presents new research examining how the peer environment works together with genetic factors to influence children's and adolescents' social development. To this end, three studies utilize a quantitative genetic approach, whereas two others use molecular genetic methodologies. Covering a wide age range from early childhood to early adulthood, the studies examine different processes of gene-environment correlation and gene-environment interaction while focusing on dyadic and group-based peer experiences (e.g., friendships, peer acceptance, and peer victimization) as well as on positive and negative aspects of social development (e.g., prosocial leadership and aggression). Overall, the findings from the studies in this special issue clearly illustrate that we need to consider how genetics and the peer environment effects work together if we are to gain a more complete picture of children's and adolescents' social development.It is with great pleasure that I present this special issue: 'The Interplay Between Genetic Factors and the Peer Environment in Explaining Children's Social Adjustment. While the study of human development was long dominated by a mainly environment-focused behavioral perspective, there is now a wide consensus that virtually all aspects of human development are subject to both genetic (i.e., heritable) and environmental influences. However, the scientific study of heritability in individual differences in human behavior is not a recent phenomenon but began more than a hundred years ago. First evidence that individual differences in intelligence and behavior are heritable was provided by Charles Darwin's cousin, Sir Francis Galton (1822-1911), in his article Hereditary Talents and Character (Rushton, 1990). Galton was also the first to use a twin design to disentangle the effects of heritable and environmental factors on individual differences in behavior. The term genetics emerged only in 1909 with the rediscovery of Mendel's laws.Quantitative genetic studies based on twin, family, or adoption designs were the main tool of research into human behavioral genetics for several decades. In contrast to molecular genetic studies, quantitative genetic studies do not measure specific genes and often do not even include any specific measure of the environment. Instead, the relative strength of genetic and environmental effects is statistically inferred by examining the similarity of family members with varying degrees of genetic relatedness, such as identical and fraternal twins (Falconer, 1996). Findings from such studies have shown that basically all facets of human development, including social behavior such as aggression or withdrawal, are influenced by both genetic and environmental factors (Turkheimer, 2000). Now, advances in molecular genetics and the completion of the DNA sequencing of the human genome (Collins, Morgan, & Patrinos, 2004) make it possible to identify specific genes implicated in interindividual differences in social behavior. Many scholars initially expected that genetic and environmental influences on human development work independently of each other (Kidd, 1991). Others have argued, however, that genes and environments are likely to interact as well as to influence each other reciprocally (Allen, Knobloch, & Pasamanick, 1961; Plomin, DeFries, & Loehlin, 1977; Scarr & McCartney, 1983). In line with this notion, there is now a growing body of research showing that genetic and environmental effects work together to shape behavioral development through various mechanisms of gene-environment interplay.Most studies on the interplay of genetic factors with the social environment have focused on the family environment such as parenting behavior or child maltreatment (Bellani, Nobile, Bianchi, Van Os, & Brambilla, 2012; Burt, Klahr, Neale, & Klump, 2013; Thapar, Harold, Rice, Langley, & O'Donovan, 2007). …

A developmental science commentary on Charney's “Behavior genetics and postgenomics”

Charney's target article convincingly demonstrates the need for the discipline of quantitative human behavior genetics to discard its false assumptions and to employ the techniques, assumptions, and research program characteristic of modern developmental psychobiology.

Heritability estimates in behavior genetics: Wasn't that station passed long ago?

Charney describes several mechanisms that will bias estimates of heritability in unpredictable directions. In addition, the mechanisms described by Charney explain the puzzling fact that research in human-behavior genetics routinely reports higher heritabilities than animal studies do. However, I argue that the concept of heritability has no real place in human research anyway.

The hunt for gene effects pertinent to behavioral traits and psychiatric disorders: From mouse to human

The field of behavioral genetics was reviewed in the classic 1960 text by Fuller and Thompson. Since then, there has been remarkable progress in the genetic analysis of animal behavior. Many molecular genetic methods in common use today were not even anticipated in 1960. Animal models for many human psychiatric disorders have been discovered or created. In human behavior genetics, however, powerful new methods have failed to reveal even one bona fide, replicable gene effect pertinent to the normal range of variation in intelligence and personality. There is no explanatory or predictive value in that genetic information. For several psychiatric disorders, including autism and schizophrenia, many large genetic effects arise from de novo mutations. Genetically, the disorders are heterogeneous; different cases with the same diagnosis have different causes. The promises of the molecular genetic revolution have not been fulfilled in behavioral domains of most interest to human psychology.

Why are children in the same family so different from one another?

One of the most important findings that has emerged from human behavioral genetics involves the environment rather than heredity, providing the best available evidence for the importance of environmental influences on personality, psychopathology, and cognition. The research also converges on the remarkable conclusion that these environmental influences make two children in the same family as different from one another as are pairs of children selected randomly from the population. The theme of the target article is that environmental differences between children in the same family (called "nonshared environment") represent the major source of environmental variance for personality, psychopathology, and cognitive abilities. One example of the evidence that supports this conclusion involves correlations for pairs of adopted children reared in the same family from early in life. Because these children share family environment but not heredity, their correlation directly estimates the importance of shared family environment. For most psychological characteristics, correlations for adoptive "siblings" hover near zero, which implies that the relevant environmental influences are not shared by children in the same family. Although it has been thought that cognitive abilities represent an exception to this rule, recent data suggest that environmental variance that affects IQ is also of the nonshared variety after adolescence. The article has three goals: (1) To describe quantitative genetic methods and research that lead to the conclusion that nonshared environment is responsible for most environmental variation relevant to psychological development, (2) to discuss specific nonshared environmental influences that have been studied to date, and (3) to consider relationships between nonshared environmental influences and behavioral differences between children in the same family. The reason for presenting this article in BBS is to draw attention to the far-reaching implications of finding that psychologically relevant environmental influences make children in a family different from, not similar to, one another.

Genetics of human aggressive behaviour

A consideration of the evolutionary, physiological and anthropological aspects of aggression suggests that individual differences in such behaviour will have important genetic as well as environmental underpinning. Surveys of the likely pathways controlling the physiological and neuronal processes involved highlight, as obvious targets to investigate, genes implicated in sexual differentiation, anxiety, stress response and the serotonin neurotransmitter pathway. To date, however, association studies on single candidates have provided little evidence for any such loci with a major effect size. This may be because genes do not operate independently, but function against a background in which other genetic and environmental factors are crucial. Indeed, a series of recent studies, particularly concentrating on the serotonin and norepinephrine metabolising enzyme, monoamine oxidase A, has emphasised the necessity of examining gene by environmental interactions if the contributions of individual loci are to be understood. These findings will have major significance for the interpretation and analysis of data from detailed whole genome association studies. Functional imaging studies of genetic variants affecting serotonin pathways have also provided valuable insights into potential links between genes, brain and aggressive behaviour.

Genetic influence on human intelligence (Spearman's g): How much?

The history and conceptual background of the heritability statistic is briefly discussed. The construct of heritability is embedded in the method of structural equation modeling widely used in modern population genetics and in human behavior genetics. The application of structural equation modeling to behavioral phenotypes is shown to be a useful and informative analytic tool, as it implements the research strategy of ‘strong inference’. I describe the application of ‘strong inference’, via the use of structural equation models in the domain of human intelligence, and demonstrate its utility as a means of refuting well formulated scientific hypotheses. The construct of Spearman's g is shown to be a strongly confirmed scientific hypothesis. Genetic and environmental influences are shown to influence g differentially over time, with shared environmental influences predominating early in life, but dissipating to near zero by adulthood. The hypothesis of substantively significant genetic influence on adult g is documented by multiple lines of evidence and numerous replications.

Recent Use of Behavioral Genetics in Criminal Cases

Human behavioral genetics research has been introduced in the U.S. criminal justice system, and its use will likely become more prevalent in the near future. This presentation will discusses the recent attempts by criminal defendants to introduce genetic predisposition testimony to negate the voluntariness of their conduct, to negate mens rea, to bolster an insanity defense or as mitigating evidence during sentencing. Although courts have thus far limited such testimony, the opinions in these cases demonstrate a likelihood that such evidence will play a larger role in future cases.To watch Professor Farahany's presentation, please see the "Google Video posting": http://video.google.com/videoplay?docid=585209098810298267&hl=en.