Behavioral Genetic Research Research Articles

Admission of Drug-Selling Behaviors is Structured by Genetic and Nonshared Environmental Factors: Results from a Longitudinal Twin-Based Study

Behavioral genetic research has consistently revealed that approximately one-half of the variance in antisocial behaviors is attributable to genetic factors. Even so, there is some reason to believe that different types of antisocial behaviors may have different developmental etiologies. The current study used this possibility as a springboard to examine the genetic and environmental influences on admission of drug-selling behaviors. Analysis of twin pairs drawn from the National Longitudinal Study of Adolescent Health revealed that 38% of the variance in a continuously coded drug-selling variable was accounted for by genetic factors and 69% of the variance in a dichotomously coded drug-selling variable was the result of genetic factors. The remaining variance for both measures was explained by nonshared environmental factors. The implications that these results have for drug research are discussed and avenues for future research are offered.

The Heritability and Genetic Correlates of Mobile Phone Use: A Twin Study of Consumer Behavior

There has been almost no overlap between behavior genetics and consumer behavior research, despite each field's importance in understanding society. In particular, both have neglected to study genetic influences on consumer adoption and usage of new technologies -- even technologies as important as the mobile phone, now used by 5.8 out of 7.0 billion people on earth. To start filling this gap, we analyzed self-reported mobile phone use, intelligence, and personality traits in two samples of Australian teenaged twins (mean ages 14.2 and 15.6 years), totaling 1,036 individuals. ACE modeling using Mx software showed substantial heritabilities for how often teens make voice calls (.60 and .34 in samples 1 and 2, respectively) and for how often they send text messages (.53 and. 50). Shared family environment - including neighborhood, social class, parental education, and parental income (i.e., the generosity of calling plans that parents can afford for their teens) -- had much weaker effects. Multivariate modeling based on cross-twin, cross-trait correlations showed negative genetic correlations between talking/texting frequency and intelligence (around -.17), and positive genetic correlations between talking/texting frequency and extraversion (about .20 to .40). Our results have implications for assessing the risks of mobile phone use such as radiofrequency field (RF) exposure and driving accidents, for studying adoption and use of other emerging technologies, for understanding the genetic architecture of the cognitive and personality traits that predict consumer behavior, and for challenging the common assumption that consumer behavior is shaped entirely by culture, media, and family environment.

The Study of Sex Differences

The rise of research in behavior genetics, endocrinology, neurotransmitter systems, brain imaging, and evolutionary psychology bears witness to psychology’s increasingly biological stance. This approach has been fiercely opposed by some academic feminists. This paper examines and responds to three of their key objections: determinism (the brain as an evolved organ is unresponsive to its environment), politics (the demonstration of sex differences obstructs the goal of gender equality), and epistemology (notions of cause and effect should be replaced by the study of the social construction of gender). The second part of the paper suggests some areas of convergence between the interests of feminists and biologically minded researchers. These include the role of neuropeptides in modulating sex differences; male-female conflict at a genetic and behavioral level; the functions and social impact of peer group sex segregation; the evolution and contemporary effects of cultural transmission and the role of higher-order cognitive systems in modulating the expression of evolved emotional adaptations.

On the relationship of past to future involvement in crime and delinquency: A behavior genetic analysis

PurposeCriminologists have devoted much attention to identifying the factors that drive stability in antisocial behavior. This body of research has, however, overlooked the contributions of behavior genetic research. This study sought to blend behavior genetics with the different perspectives used by criminologists to explain stability. MethodsEmploying a behavioral genetic research design, the current study analyzed the correlation between adolescent and adulthood crime (a 13year time span was covered between the two time points) among a sample of sibling pairs drawn from the National Longitudinal Study of Adolescent Health (Add Health). ResultsThe findings revealed that genetic factors accounted for nearly all of the stability in offending behavior from adolescence to adulthood. Environmental factors (particularly, of the nonshared variety) accounted for the majority of the changes in offending. ConclusionsThe implications of these results for criminological research and theory are discussed.

Индивидуальные различия в способностях к обучению: возможности и перспективы психогенетических исследований

Малых Сергей Борисович — доктор психологических наук, профессор, член-корреспондент РАО, главный научный сотрудник лаборатории когнитивных исследований и психогенетики НИУ «Томский государственный университет». Эл. адрес: malykhsb@mail.ru Адрес: Россия, 634050, г. Томск, пр. Ленина, д. 36.Тихомирова Татьяна Николаевна — кандидат психологических наук, старший научный сотрудник лаборатории когнитивных исследований и психогенетики НИУ «Томский государственный университет». Эл. адрес: tikho@mail.ru Адрес: Россия, 634050, г. Томск, пр. Ленина, д. 36.Ковас Юлия Владимировна— PhD, заведующая лабораторией когнитивных исследований и психогенетики НИУ «Томский государственный университет», заведующая лабораторией InLab Голдсмитс-колледжа Университета Лондона. Эл. адрес: y.kovas@gold.ac.uk Адрес: Россия, 634050, г. Томск, пр. Ленина, д. 36.Подчеркивается важность научно-экспериментального изучения природы индивидуальных различий — поиска ответа на вопрос, почему в условиях относительного единообразия образовательной среды ученики отличаются друг от друга по когнитивным, личностным и мотивационным характеристикам. Показано, что индивидуальные различия в когнитивных способностях и способностях к обучению формируются в условиях сложных процессов генотип-средового взаимодействия. Для решения важнейшей образовательной задачи — повышения общего уровня академической успешности всех учащихся через индивидуально ориентированные методы обучения — предлагается использовать генетически чувствительные методы изучения механизмов, лежащих в основе индивидуальных различий в способностях к обучению в разных предметных областях.Особое внимание уделяется рассмотрению близнецового метода, с помощью которого можно провести детальное исследование когнитивного развития, способностей к обучению и нарушений способности к обучению. Важная особенность близнецового метода состоит в том, что исследования близнецов обеспечивают наилучшее из возможных доказательство значимости влияния средовых, в том числе и образовательных, факторов. Близнецовый метод дает возможность уточнить роль общей среды (условий, повышающих сходство близнецов по определенному признаку) и роль индивидуальной среды (условий, не способствующих похожести близнецов).Отмечается, что в 2012 г. начата работа по созданию Российского школьного близнецового регистра, который в перспективе может стать уникальным ресурсом для российских и международных исследователей, а также источником теоретических и практических знаний для педагогов, психологов, родителей и самих учащихся.

Shared environmental contributions to substance use.

The current study examined the association between substance use in the household during childhood, parental attitudes towards substance use and lifetime substance use in males. Subjects included 1081 monozygotic and 707 dizygotic twins from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders. Retrospective reports of substance use and features of the family environment (adult household substance use and parental attitudes towards substance use) were obtained using a life history interview. A trivariate Cholesky decomposition was conducted using the program Mx to decompose common shared environmental variance. Findings suggest that family environmental factors accounted for a large proportion of the shared environmental effects for illicit drug use. Results illustrate an important way of extending behavior genetic research to reveal specific etiological environmental mechanisms.

Biopsychosocial Models and the Study of Family Processes and Child Adjustment

Biopsychosocial Models and the Study of Family Processes and Child Adjustment

Understanding Family Process and Child Adjustment Through Behavioral Genetic Research: A Reply

The contribution of both genes and environments on family relationships is reviewed in Horwitz and Neiderhiser (2011). This recognition is due to two simultaneous movements in the fields of both family process and behavioral genetics. Specifically, family researchers have been incorporating strategies that allow for the estimation of genetic effects in their studies and genetic researchers have been directly measuring family processes. The commentaries by Calkins (2011) and Deater-Deckard (2011) help to highlight the promise and limitations of this work to date and, together with our article, provide guidance for where this work can and should go in the future. In all three papers the focus is clearly on moving beyond simply examining genes and environments as independent factors. Instead, there is both a need and an emphasis on how genes and environments work together. We welcome the opportunity to both expand on the article and to use the suggestions made in the commentaries to discuss current and future directions of research on gene - environment interplay. Three points will be made in this response. First, in conjunction with the comments made by Deater-Deckard, we discuss how work in gene - environment interplay may be expanded to clarify different processes in different dyads within the family system. Second, we use emerging work in gene - environment interplay to elaborate on mechanisms. Specifically, in response to the comments made by Calkins, we describe work that is engaged in disentangling genes, environments, and potential underlying biological processes. Third, we discuss improvements that must be made in both family research and genetic research in order to advance our understanding of gene - environment interplay within the family. Throughout each of these sections we integrate the suggestions and comments of both Calkins and Deater-Deckard with our article to present a unified set of recommendations for the fields. GENE -ENVIRONMENT INTERPLAY AS A STRATEGY FOR UNDERSTANDING FAMILY PROCESS Deater-Deckard underscored the importance of behavioral genetic work for delineating sources of within-family variation in qualities of each family relationship and each child's outcome. Indeed, by demonstrating when genetic or environmental influences, or both, contribute to these associations we have discovered that different dyads within the family influence family relationships and child functioning for different reasons (e.g., Reiss, 2010). For example, genetic influences have been found to account for a sizable portion of the association between hostile and critical parent -adolescent interactions and adolescent antisocial behavior. This suggests that children's heritable characteristics evoked interactions with parents that in turn contributed to their maladjustment (e.g., Reiss, 2010). Additional work has demonstrated that shared environmental influences accounted for the majority of the covariation between mother -child and sibling relationships, indicating that siblings model their relationships with their mother when siblings interact with one another (Bussell et al., 1999). Sibling relationships were also linked to a broad range of adolescent adjustment measures, and shared environmental influences contributed to these linkages (Reiss, Neiderhiser, Hetherington, & Plomin, 2000). Together, this set of findings indicates that children's genotypes are important for understanding their relationships with their mothers, whereas siblings are important for shaping each others' adjustment. Hence, this work illustrates the utility of behavioral genetic research for delineating sources of within- family variation in qualities of each family relationship and each child's outcome. Deater-Deckard further raised the need for more research focused on differentiating individual-level processes (i.e., actor and partner effects) from dyadic level processes using the behavioral genetic extension of the social relations model. …

Families and Genomes: The Next Generation

I thought this was about family relations and child development. Why are we reading and talking about genes? . Many of us who teach and study genetics and human behavior get questions like this from our students and our colleagues. My answer to this kind of question is informed by the ongoing work presented by Horwitz and Neiderhiser (2011), and it goes something like this: Our cultures and our genomes have coevolved for millennia. The continually changing products of this ongoing process include different versions of many genes (i.e., alleles) that covary and interact with variability in environments. Efforts to understand the impact of this ongoing process require consideration of family relationships. Successful reproduction and survival of offspring are ensured within the intense, lifelong social relationships formed in family groups, where individual differences between people develop. Over the course of the 20th century, theorists in every scientific discipline came to realize that they needed to incorporate genetic influences into conceptualizations of human functioning and behavior. Now we find ourselves living in the era of the genome. Every week, new discoveries are published that tell us something about genes and their influence on human functioning. So here is my question. As students and scholars of family and human development, will we be able to move family and developmental research and practice toward a more complete understanding of the role of genetics in family relations and child outcomes? We probably will succeed, if we take seriously the important and complex concepts, methods, and conclusions offered by Horwitz and Neiderhiser (201 1) in their review of behavioral genetic research on family relationships and child adjustment. They present the breadth and leading edge of genetically informative research addressing gene - environment interplay in marital and family relationships and outcomes in children. Their paper offers a clear and compelling message about what we know, and what lies ahead, for family and developmental scientists. Theories about gene - environment transactions are tested using quasi-experimental behavioral genetic studies based on different types of kin (e.g., adoptive and nonadoptive parent -child pairs, identical and fraternal twin siblings, full and half siblings) and molecular genetic studies that directly assess the structural variation in DNA and its associations with behaviors of interest. Gone are the days of simply estimating a heritability coefficient and arguing that this variable or that variable includes some kind of genetic influence. Now there are computational methods for considering gene - environment interplay between genetic and nongenetic factors. This includes the correlated and interacting effects highlighted by Horwitz and Neiderhiser. FAMILIES AND GENOMES Gene -environment interplay produces remarkable within-family variation in each individual's many personal attributes, as well as variation in each dyadic relationship. Paying attention to this within-family variability - rather than limiting the analysis to differences between families or groups - strengthens understanding of the bidirectional nature of family relationships and children's development in families (Reiss, Neiderhiser, Hetherington, & Plomin, 2000). Within families are substantial sibling differences in temperament and personality factors, cognitive and achievement skills, and many other individual difference attributes arising from genetic and nongenetic influences. Full siblings share 50% of their alleles identical by descent, on average, but there is noteworthy deviation from this average level of genetic similarity. The physical and behavioral similarity of siblings varies widely, due in part to variation in genetic similarity. But nongenetic factors matter, too, and are defined as nonshared environmental processes that enhance sibling differentiation. The behavioral genetic models described by Horwitz and Neiderhiser (201 1) generate mathematical constructs representing heritable and nonheritable influences. …

Gene-Environment Interplay, Family Relationships, and Child Adjustment

This paper reviews behavioral genetic research from the past decade that has moved beyond simply studying the independent influences of genes and environments. The studies considered in this review have instead focused on understanding gene - environment interplay, including genotype - environment correlation ( rGE) and genotype × environment interaction (G × E). Studies have suggested that rGE is an important pathway through which family relationships are associated with child adjustment. Also important are direct causal influences of family relationships on child adjustment, independent of genetic confounds. Other studies have indicated that genetic and environmental influences on child adjustment are moderated by different levels of family relationships in G × E interactions. Genetically informed studies that have examined family relations have been critical to advancing our understanding of gene - environment interplay.

Genetic Influences on Adolescent Eating Habits

Behavioral genetic research shows that variation in eating habits and food consumption is due to genetic and environmental factors. The current study extends this line of research by examining the genetic contribution to adolescent eating habits. Analysis of sibling pairs drawn from the National Longitudinal Study of Adolescent Health (Add Health) revealed significant genetic influences on variance in an unhealthy eating habits scale (h(2) = .42), a healthy eating habits scale (h(2) = .51), the number of meals eaten at a fast-food restaurant (h(2) = .33), and the total number of meals eaten per week (h(2) = .26). Most of the remaining variance was due to nonshared environmental factors. Additional analyses conducted separately for males and females revealed a similar pattern of findings. The authors note the limitations of the study and offer suggestions for future research.

How Genes Influence Behaviorby FlintJonathan, GreenspanRalph J., and KendlerKenneth S., New York, Oxford University Press, 2010, 304 pp., $52.95.

How Genes Influence Behaviorby FlintJonathan, GreenspanRalph J., and KendlerKenneth S., New York, Oxford University Press, 2010, 304 pp., $52.95.

A twin and adoption study of reading achievement: Exploration of shared-environmental and gene–environment-interaction effects

Existing behavior-genetic research implicates substantial influence of heredity and modest influence of shared environment on reading achievement and reading disability. Applying DeFries–Fulker analysis to a combined sample of twins and adoptees (N = 4886, including 266 reading-disabled probands), the present study replicates prior findings of considerable heritability for both reading achievement and reading disability. A simple biometric model adequately described parent and offspring data (combined N = 9430 parents and offspring) across differing types of families present in the sample Analyses yielded a high heritability estimate (around 0.70) and a negligible shared-environmentality estimate for both reading achievement and reading disability. No evidence of gene × environment interaction was found for parental reading ability and parental educational attainment, the two moderators analyzed.

Zebrafish behavioural assays of translational relevance for the study of psychiatric disease

Understanding the pathogenesis of the complex behavioural disorders that constitute psychiatric disease is a major challenge for biomedical research. Assays in rodents have contributed significantly to our understanding of the neural basis of behavioural disorders and continue to be one of the main focuses for the development of novel therapeutics. Now, owing to their genetic tractability and optical transparency (allowing in vivo imaging of circuit function) and the rapid expansion of genetic tools, zebrafish are becoming increasingly popular for behavioural genetic research. The increased development of behavioural assays in zebrafish raises the possibility of exploiting the advantages of this system to identify molecular mechanisms contributing to behavioural phenotypes associated with psychiatric disorders as well as potential therapeutics. This mini-review describes behavioural paradigms in zebrafish that can be used to address endophenotypes associated with psychiatric disease. The content reflects the interests of the author and covers tests of cognitive functions, response choice and inhibition, social interaction and executive function.

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Dogs are sometimes referred to as "man's best friend" and with the increase in urbanization and lifestyle changes, dogs are seen by their owners as family members. Society expresses specific concerns about the experimental use of dogs, as they are sometimes perceived to have a special status for humans. This may appear somewhat conflicting with the idea that the intrinsic value of all animals is the same, and that also several other animal species are used in biomedical research and toxicology. This aspect and many others are discussed in an introductory chapter dealing with ethical considerations on the use of dogs as laboratory animals. The report gives an overview on the use of dogs in biomedical research, safety assessment and the drug developmental process and reflects the discussion on the use of dogs as second (non-rodent)species in toxicity testing. Approximately 20,000 dogs are used in scientific procedures in Europe every year, and their distinct genetic, physiological and behavioral characteristics may support their use as models for e.g. behavioral analysis and genetic research. Advances in the 3Rs (Replacement, Reduction and Refinement of experiments using dogs) are described, potential opportunities are discussed and recommendations for further progress in this area are made.

Biologically constrained behavioral genetics research

From a biologist's perspective, social behavior includes any behavior that involves at least two actors. By this definition, social behavior can include aggregation in slime molds, the colony structure of the eusocial insects, or the coordinated efforts of humans across vast distances to successfully land on the moon. The diversity of this range of behavior shares one driving force: natural selection. While natural selection acts at the level of phenotype (e.g., morphology, metabolism, behavior) the ultimate unit of natural selection is the gene contained in DNA-the object of inheritance. The relationship between DNA and social behavior is uncovered in the field of sociogenomics, defined as the mechanistic study of genes, gene products, and gene × gene interaction networks supporting emergent social behaviors.

Biologically constrained behavioral genetics research

From a biologist's perspective, social behavior includes any behavior that involves at least two actors. By this definition, social behavior can include aggregation in slime molds, the colony structure of the eusocial insects, or the coordinated efforts of humans across vast distances to successfully land on the moon. The diversity of this range of behavior shares one driving force: natural selection. While natural selection acts at the level of phenotype (e.g., morphology, metabolism, behavior) the ultimate unit of natural selection is the gene contained in DNA-the object of inheritance. The relationship between DNA and social behavior is uncovered in the field of sociogenomics, defined as the mechanistic study of genes, gene products, and gene × gene interaction networks supporting emergent social behaviors.

Emergence of a Gene × Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years

Recent research in behavioral genetics has found evidence for a Gene × Environment interaction on cognitive ability: Individual differences in cognitive ability among children raised in socioeconomically advantaged homes are primarily due to genes, whereas environmental factors are more influential for children from disadvantaged homes. We investigated the developmental origins of this interaction in a sample of 750 pairs of twins measured on the Bayley Short Form test of infant mental ability, once at age 10 months and again at age 2 years. A Gene × Environment interaction was evident on the longitudinal change in mental ability over the study period. At age 10 months, genes accounted for negligible variation in mental ability across all levels of socioeconomic status (SES). However, genetic influences emerged over the course of development, with larger genetic influences emerging for infants raised in higher-SES homes. At age 2 years, genes accounted for nearly 50% of the variation in mental ability of children raised in high-SES homes, but genes continued to account for negligible variation in mental ability of children raised in low-SES homes.

The Effects of Nonshared Environments on Adolescent Depression: Findings From a Sample of Monozygotic Twins

Behavioral genetic research has revealed that nonshared environments are associated with depression and depressive symptomatology. Research examining specific nonshared environments related to adolescent depression remains relatively limited. To address this gap in the published data, we analyzed a sample of monozygotic (MZ) twin pairs from the National Longitudinal Study of Adolescent Health (Add Health) to examine the effects of nonshared environmental variables on adolescent depression. We used the MZ-twin-difference-scores method on data from MZ twins (n = 289 twin pairs) drawn from the Add Health to examine the effect of specific nonshared environments on adolescent depression. Findings from the MZ-difference-scores analyses revealed that between-twin differences in maternal disengagement were significantly related to differences in adolescent depression. Additional analyses revealed that the association between adolescent depression and maternal disengagement was largely a child-driven effect. Compared with previous research that has implicated maternal socialization in the development of depression among adolescents, the results of the current study revealed that differences in maternal socialization were a response and not a cause of adolescent depression.

Serotonin transporter promoter region (5‐HTTLPR) polymorphism predicts resting respiratory sinus arrhythmia

Respiratory sinus arrhythmia (RSA) is often conceptualized as an index of physiological flexibility that has been related to emotion regulatory capacity. Although behavioral genetics research indicates that RSA is partly heritable, relatively few molecular genetics studies have been conducted. We examined whether the serotonin transporter promoter region (5-HTTLPR) polymorphism was associated with resting RSA among healthy young adults (N=71). Short 5-HTTLPR allele carriers had significantly lower resting RSA than long 5-HTTLPR homozygotes. Genotype explained 5% of the variance in resting RSA. Although firm conclusions depend on further study, the short allele of the 5-HTTLPR polymorphism may contribute to individual differences in RSA and its behavioral correlates.