Genes and Politics: A New Explanation and Evaluation of Twin Study Results and Association Studies in Political Science

2013 ◽  
Vol 21 (3) ◽  
pp. 350-367 ◽  
Author(s):  
Doron Shultziner
Keyword(s):  
Political Science ◽  
Genetic Basis ◽  
Behavioral Genetics ◽  
Association Studies ◽  
Twin Studies ◽  
Future Research ◽  
Voting Turnout ◽  
Study Results ◽  
Heritability Estimates ◽  
And Function

This article offers a new explanation for the results of twin studies in political science that supposedly disclose a genetic basis for political traits. I argue that identical twins tend to be more alike than nonidentical twins because the former are more similarly affected by the same environmental conditions, but the content of those greater trait similarities is nevertheless completely malleable and determined by particular environments. The twin studies method thus can neither prove nor refute the argument for a genetic basis of political traits such as liberal and conservative preferences or voting turnout. The meaning of heritability estimates results in twin studies are discussed, as well as the definition and function of the environment in the political science twin studies. The premature attempts to associate political traits with specific genes despite countertrends in genetics are also examined. I conclude by proposing that the alternative explanation of this article may explain certain puzzles in behavioral genetics, particularly why social and political traits have higher heritability estimates than common physical and medical traits. I map the main point of disagreements with the methodology and the interpretation of its results, and delineate the main operative implications for future research.

Twin Studies and Politics

2019 ◽  
Author(s):  
Levente Littvay
Keyword(s):  
Political Science ◽  
Behavioral Genetics ◽  
Twin Studies ◽  
Social Scientists ◽  
Cross Sectional ◽  
Genetic Transmission ◽  
The Social ◽  
Direction Of Causation ◽  
Social Part ◽  
The Impact

As recently as 2005, John Alford and colleagues surprised political science with their twin study that found empirical evidence of the genetic transmission of political attitudes and behaviors. Reactions in the field were mixed, but one thing is for sure: it is not time to mourn the social part of the social sciences. Genetics is not the deterministic mechanism that social scientists often assume it to be. No specific part of DNA is responsible for anything but minute, indirect effects on political orientations. Genes express themselves differently in different contexts, suggesting that the political phenomenon behavioral political scientists take for granted may be quite volatile; hence, the impact of genetics is also much less stable in its foundations than initially assumed. Twin studies can offer a unique and powerful avenue to study these behavioral processes as they are more powerful than cross-sectional (or even longitudinal) studies not only for understanding heritability but also for asserting the direction of causation, the social (and, of course, genetic) pathways that explain how political phenomena are related to each other. This chapter aims to take the reader through this journey that political science has gone through over the past decade and a half and point to the synergies behavioral political science and behavioral genetics offer to the advancement of the discipline.

Refractive Errors in Twin Studies

2006 ◽  
Vol 9 (4) ◽  
pp. 566-572 ◽  
Author(s):  
Mohamed Dirani ◽  
Matthew Chamberlain ◽  
Pam Garoufalis ◽  
Christine Chen ◽  
Robyn H. Guymer ◽  
...  
Keyword(s):  
Data Collection ◽  
Refractive Error ◽  
Genetic Basis ◽  
Twin Studies ◽  
Refractive Errors ◽  
Twin Model ◽  
Wide Range ◽  
Heritability Estimates

AbstractIt is estimated that 1.6 billion people worldwide have myopia, a refractive error, and this number is expected to increase to approximately 2.5 billion by the year 2020. It is now well established that both the environment and genetics play a role in the development of myopia. However, the exact contribution of each of these components to myopia development has yet to be completely determined. Twin studies (classical twin model) are commonly used to determine the weighting of genetic and environmental components in disease. Over the last century, twin studies have investigated the heritability of refractive errors in different sample populations and have collectively supported a genetic basis to refractive errors. However, different sample populations and methods of data collection have produced a wide range of heritability estimates ranging from .5 to .9. This article will review those twin studies that have investigated refractive error, particularly myopia, as well as biometric measures linked to refractive error, to compare heritability estimates and methodology designs.

What is the impact of genome-wide supported risk variants for schizophrenia and bipolar disorder on brain structure and function? A systematic review

2015 ◽  
Vol 45 (12) ◽  
pp. 2461-2480 ◽  
Author(s):  
R. Gurung ◽  
D. P. Prata
Keyword(s):  
Bipolar Disorder ◽  
Brain Structure ◽  
Association Studies ◽  
Structure And Function ◽  
Future Research ◽  
Genome Wide Association Studies ◽  
Genome Wide ◽  
Brain Structure And Function ◽  
And Function ◽  
The Impact

The powerful genome-wide association studies (GWAS) revealed common mutations that increase susceptibility for schizophrenia (SZ) and bipolar disorder (BD), but the vast majority were not known to be functional or associated with these illnesses. To help fill this gap, their impact on human brain structure and function has been examined. We systematically discuss this output to facilitate its timely integration in the psychosis research field; and encourage reflection for future research. Irrespective of imaging modality, studies addressing the effect of SZ/BD GWAS risk genes (ANK3, CACNA1C, MHC, TCF4, NRGN, DGKH, PBRM1, NCANandZNF804A) were included. Most GWAS risk variations were reported to affect neuroimaging phenotypes implicated in SZ/BD: white-matter integrity (ANK3andZNF804A), volume (CACNA1CandZNF804A) and density (ZNF804A); grey-matter (CACNA1C, NRGN, TCF4andZNF804A) and ventricular (TCF4) volume; cortical folding (NCAN) and thickness (ZNF804A); regional activation during executive tasks (ANK3, CACNA1C, DGKH, NRGNandZNF804A) and functional connectivity during executive tasks (CACNA1CandZNF804A), facial affect recognition (CACNA1CandZNF804A) and theory-of-mind (ZNF804A); but inconsistencies and non-replications also exist. Further efforts such as standardizing reporting and exploring complementary designs, are warranted to test the reproducibility of these early findings.

Genetic contributions to anxiety disorders: where we are and where we are heading

2021 ◽  
pp. 1-16
Author(s):  
Helga Ask ◽  
Rosa Cheesman ◽  
Eshim S. Jami ◽  
Daniel F. Levey ◽  
Kirstin L. Purves ◽  
...  
Keyword(s):  
Anxiety Disorders ◽  
Psychiatric Disorders ◽  
Large Scale ◽  
Current Knowledge ◽  
Association Studies ◽  
Twin Studies ◽  
Future Research ◽  
Specific Gene ◽  
Genome Wide Association Studies ◽  
Genome Wide

Abstract Anxiety disorders are among the most common psychiatric disorders worldwide. They often onset early in life, with symptoms and consequences that can persist for decades. This makes anxiety disorders some of the most debilitating and costly disorders of our time. Although much is known about the synaptic and circuit mechanisms of fear and anxiety, research on the underlying genetics has lagged behind that of other psychiatric disorders. However, alongside the formation of the Psychiatric Genomic Consortium Anxiety workgroup, progress is rapidly advancing, offering opportunities for future research. Here we review current knowledge about the genetics of anxiety across the lifespan from genetically informative designs (i.e. twin studies and molecular genetics). We include studies of specific anxiety disorders (e.g. panic disorder, generalised anxiety disorder) as well as those using dimensional measures of trait anxiety. We particularly address findings from large-scale genome-wide association studies and show how such discoveries may provide opportunities for translation into improved or new therapeutics for affected individuals. Finally, we describe how discoveries in anxiety genetics open the door to numerous new research possibilities, such as the investigation of specific gene–environment interactions and the disentangling of causal associations with related traits and disorders. We discuss how the field of anxiety genetics is expected to move forward. In addition to the obvious need for larger sample sizes in genome-wide studies, we highlight the need for studies among young people, focusing on specific underlying dimensional traits or components of anxiety.

Modeling the Genetics of Social Cognition in the Laboratory

2014 ◽  
Author(s):  
Richard P. Ebstein ◽  
Songfa Zhong ◽  
Robin Chark ◽  
Poh San Lai ◽  
Soo Hong Chew
Keyword(s):  
Decision Making ◽  
Social Cognition ◽  
Association Studies ◽  
Twin Studies ◽  
Future Research ◽  
Genome Wide Association Studies ◽  
Behavioral Economic ◽  
Social Decision ◽  
Wide Range ◽  
Social Decision Making

This chapter examines recent advances in the genetics of social cognition, discussing evidence from twin studies that confirm the relevancy of genetic hard wiring in understanding many social phenotypes, with important implications for the social sciences and for genome-wide association studies (GWAS) that may identify specific genes contributing to a wide range of social phenotypes, genoeconomics, and individual and social decision making. Stressing the importance of phenotype definition and precise measurement as key to success in GWAS, the authors argue that laboratory-based behavioral economic paradigms using ethnically homogenous student populations generate the best prospects for successful GWAS. Also discussed are the neurochemical/neurogenetic architecture of behavioral economic games that measure individual and social decision making and the considerable progress made in unraveling the neurogenetics of human parenting and the beginning of a political attitudes neuroscience. The authors’ own GWAS is used to present a set of guidelines for future research directions.

Genetics of Panic Disorder

CNS Spectrums ◽  
1999 ◽  
Vol 4 (6) ◽  
pp. 62-70
Author(s):  
Donatella Marazziti ◽  
Alessandro Rotondo
Keyword(s):  
Panic Disorder ◽  
Anxiety Disorders ◽  
Candidate Genes ◽  
Association Studies ◽  
Twin Studies ◽  
Future Research ◽  
Genetic Investigation ◽  
Psychiatric Genetic ◽  
Genetic Mechanisms ◽  
Nosologic Entity

ABSTRACTSystematic studies on the genetics of panic disorder as a distinct nosologic entity separate from anxiety disorders date back to the 1980s. It is, therefore, a relatively new topic for psychiatric genetic investigation. For this reason, available data are not numerous, but findings ensuing from “classical” methods, such as family and twin studies, suggest the involvement of genetic mechanisms to a broad extent, confirmed by the most recent studies. The approaches of molecular genetics, particularly linkage analyses and association studies exploring candidate genes, have led to inconclusive results but have also provided interesting findings that need to be tested in future research.

scholarly journals The chromosome-based lavender genome provides new insights into Lamiaceae evolution and terpenoid biosynthesis

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jingrui Li ◽  
Yiming Wang ◽  
Yanmei Dong ◽  
Wenying Zhang ◽  
Di Wang ◽  
...  
Keyword(s):  
Gene Networks ◽  
Genetic Basis ◽  
Glandular Trichomes ◽  
Gene Families ◽  
Gene Clusters ◽  
Future Research ◽  
Terpenoid Biosynthesis ◽  
Insect Communication ◽  
Volatile Terpenoids ◽  
And Function

AbstractThe aromatic shrub Lavandula angustifolia produces various volatile terpenoids that serve as resources for essential oils and function in plant-insect communication. To better understand the genetic basis of the terpenoid diversity in lavender, we present a high-quality reference genome for the Chinese lavender cultivar ‘Jingxun 2’ using PacBio and Hi-C technologies to anchor the 894.50 Mb genome assembly into 27 pseudochromosomes. In addition to the γ triplication event, lavender underwent two rounds of whole-genome duplication (WGD) during the Eocene–Oligocene (29.6 MYA) and Miocene–Pliocene (6.9 MYA) transitions. As a result of tandem duplications and lineage-specific WGDs, gene families related to terpenoid biosynthesis in lavender are substantially expanded compared to those of five other species in Lamiaceae. Many terpenoid biosynthesis transcripts are abundant in glandular trichomes. We further integrated the contents of ecologically functional terpenoids and coexpressed terpenoid biosynthetic genes to construct terpenoid-gene networks. Typical gene clusters, including TPS-TPS, TPS-CYP450, and TPS-BAHD, linked with compounds that primarily function as attractants or repellents, were identified by their similar patterns of change during flower development or in response to methyl jasmonate. Comprehensive analysis of the genetic basis of the production of volatiles in lavender could serve as a foundation for future research into lavender evolution, phytochemistry, and ecology.

scholarly journals Does Second Language Learning Promote Neuroplasticity in Aging? A Systematic Review of Cognitive and Neuroimaging Studies

2021 ◽  
Vol 13 ◽  
Author(s):  
Caitlin Ware ◽  
Sophie Dautricourt ◽  
Julie Gonneaud ◽  
Gael Chételat
Keyword(s):  
Older Adults ◽  
Second Language ◽  
Language Learning ◽  
Cognitive Abilities ◽  
Second Language Learning ◽  
Later Life ◽  
Future Research ◽  
Study Results ◽  
Brain Structure And Function ◽  
And Function

As the population ages, understanding how to maintain older adults' cognitive abilities is essential. Bilingualism has been linked to higher cognitive reserve, better performance in executive control, changes in brain structure and function relative to monolinguals, and delay in dementia onset. Learning a second language thus seems a promising avenue for cognitive enhancement in older adults. Our review aims to determine whether learning a foreign language in later life improves cognition and promotes neuroplasticity. We screened articles from the Pubmed, Scopus, and Science Direct databases to identify interventional studies using second language training in senior participants, including either cognition or neuroimaging as outcome measures. A total of nine articles were found, with only one neuroimaging study. Results from these studies are inconsistent, but tend to suggest that second language learning is associated with improvement in attentional switching, inhibition, working memory, and increased functional connectivity. We discuss the implications of these results, and suggest new directions and methodological recommendations for future research.

scholarly journals Genetics of obsessive–compulsive disorder

2020 ◽  
pp. 995-1002
Author(s):  
Gerald Nestadt ◽  
Jack Samuels
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Genetic Basis ◽  
Rare Variants ◽  
Association Studies ◽  
Molecular Genetic ◽  
Twin Studies ◽  
Obsessive Compulsive ◽  
Genetic Studies ◽  
Compulsive Disorder ◽  
Candidate Gene Association

There is strong evidence that obsessive–compulsive disorder (OCD) has a genetic basis. This chapter focuses on recent findings on the genetics of OCD from genetic epidemiological (family and twin) studies, as well as from molecular genetic studies (linkage studies, candidate gene association studies, and genome-wide association studies), of common and rare variants associated with OCD. The chapter discusses the challenges and prospects in elucidating the specific genetic basis of OCD, including the genetic complexity and phenotypic definition. Genetic studies in humans and animals offer great promise in elucidating the pathophysiology of OCD and in developing more rational treatment approaches.

scholarly journals Heritability of Sleep and Its Disorders in Childhood and Adolescence

2021 ◽  
Author(s):  
Katie J. S. Lewis ◽  
Alice M. Gregory
Keyword(s):  
Sleep Problems ◽  
Association Studies ◽  
Full Range ◽  
Current Evidence ◽  
Future Research ◽  
Childhood And Adolescence ◽  
Genome Wide Association Studies ◽  
Genes And Environment ◽  
Wide Range ◽  
Heritability Estimates

Abstract Purpose of Review This review summarizes recent literature on the heritability of sleep and sleep disorders in childhood and adolescence. We also identify gaps in the literature and priorities for future research. Recent Findings Findings indicate that age, measurement method, reporter, and timing of sleep measurements can influence heritability estimates. Recent genome-wide association studies (GWAS) have identified differences in the heritability of sleep problems when ancestral differences are considered, but sample sizes are small compared to adult GWAS. Most studies focus on sleep variables in the full range rather than on disorder. Studies using objective measures of sleep typically comprised small samples. Summary Current evidence demonstrates a wide range of heritability estimates across sleep phenotypes in childhood and adolescence, but research in larger samples, particularly using objective sleep measures and GWAS, is needed. Further understanding of environmental mechanisms and the interaction between genes and environment is key for future research.

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