Misconceptions, Experimental Design, and Behavioral Genetics
Gail S. Anderson in Biological Influences on Criminal Behavior, 2019
Adoption studies separate the genetic and environmental influences on behavior more completely by comparing an adopted child’s behavior with the behaviors of the biological parents and siblings and those of the adoptive family. Many countries, particularly those of northern Europe, keep very thorough registries that record everything about a person—not just birth, death, and marriage but also health, therapeutic drug use, drug and alcohol abuse, adoption, criminal record, criminal arrests, and much more. Each record can be searched, as each individual has a unique identifier number and can be traced through multiple registries. Although this does raise concerns about privacy, the registries are a treasure trove for researchers, as adoption, time of adoption, length of time in biological home, length of time in adopted home, schooling, antisocial behavior, arrest, and criminal record can be determined for all adoptees, as well as their biological and adoptive families.
Genetic influences on antisocial behaviour, problem substance use and schizophrenia: evidence from quantitative genetic and molecular genetic studies
John C. Gunn, Pamela J. Taylor in Forensic Psychiatry, 2014
Adoption studies are based on the premise that adoptees share their genes but not their environment with their biological relatives and their environment but not their genes with their adoptive families, thus making it possible to establish the significance of each influence separately. There are two main types of adoption studies (Kringlen, 1991). The adoptees’ method compares the adopted-away offspring of biological parents affected with a condition with control adoptees whose biological parents were unaffected. The adoptees’ relatives’ method compares the biological and adoptive relatives of affected adoptees with those of non-affected control adoptees. In both designs, a higher prevalence of the disorder amongst adoptees with affected biological relatives suggests that genetic factors play a role. A higher prevalence of disorder in adoptees with affected adoptive parents than those with non-affected adoptive parents suggests that environmental factors play a role. Such studies require cases and controls to be matched on relevant covariates, such as age, sex, socioeconomic status of the adoptive family and time spent with the biological mother (Ingraham and Kety, 2000).
Overview of the Adoption Studies
Claude Bouchard in The Genetics of Obesity, 2020
Adoption studies that include both biological parents and biological siblings of the adoptee allow a distinction between the two effects. If the only genetic effects on obesity were additive ones, the correlation between adoptees and their biological parents should be similar to the correlation between adoptees and their biological full siblings and double the correlation between the adoptees and their biological half siblings. The Danish study is the only one that includes these biological relationships.23,26,27 It showed the pattern found in natural families, suggesting the presence of nonadditivity and major gene effects.25 The comprehensive model analysis, however, does not support such effects,24,30 although there is some evidence to support the existence of major single gene effects (see 7).
Perceived Stress and Sleep Quality in Midlife and Later: Controlling for Genetic and Environmental Influences
Published in Behavioral Sleep Medicine, 2020
Yueqin Hu, Marieke Visser, Sierra Kaiser
In addition to these hypotheses, given the possible heritability of perceived stress and sleep quality, we will also analyze the influence of additive genetics, shared environment and individual-specific environment in the stress–sleep relationship. Behavior genetics by means of twin, family and adoption studies can help decipher the relative contribution of genetic and environmental variability in behavioral traits (Moore et al., 2011). This study will employ the methods of behavior genetics, and use the ACE model (Boomsma, Busjahn, & Peltonen, 2002; Falconer, 1960; Neale & Cardon, 1992) on monozygotic twins and dizygotic twins to separate the contribution of genes, shared environment, and individual-specific environment. Then, for variables that are largely influenced by genes and shared environment, we will use the co-twin design (CTC, e.g, Burt et al., 2010; McGue, Osler, & Christensen, 2010) to control for any genetic and familial confounds.
The Association of Optimism with Sleep Duration and Quality: Findings from the Coronary Artery Risk and Development in Young Adults (CARDIA) Study
Published in Behavioral Medicine, 2020
Rosalba Hernandez, Thanh-Huyen T. Vu, Kiarri N. Kershaw, Julia K. Boehm, Laura D. Kubzansky, Mercedes Carnethon, Claudia Trudel-Fitzgerald, Kristen L. Knutson, Laura A. Colangelo, Kiang Liu
Emerging science is moving in the direction of developing interventions to boost psychological well-being domains, including optimism, to promote better health practices. Although heritability or genetic determinism is involved when characterizing facets of psychological well-being, twin and adoption studies support malleability where 40% of observed variance in well-being is accounted for by intentional behavioral practices that are alterable and teachable 16. If intervention development is to be pursued, however, more robust evidence of the link between optimism and sleep from prospective studies are needed (as few exist);17,18 in addition, such studies will benefit from inclusion of more diverse samples and objective markers of sleep quality and duration. Clear shortcomings exist within this emerging body of work as the link between optimism and sleep remains relatively ambiguous given attributable scarcity and overreliance on cross-sectional designs and self-reported measures. Using data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a large multi-center cohort study in the United States, we examined the cross-sectional and prospective association of optimism with self-reported ratings and objective measures of sleep quality and duration—with exploration of plausible mediation via depressive symptoms. We hypothesized that persons with higher optimism levels would be more likely to have favorable sleep patterns independently of socio-demographic factors, self-reported physical health status, and depressive symptoms.
On the path toward personalized medicine: implications of pharmacogenetic studies of alcohol use disorder medications
Published in Expert Review of Precision Medicine and Drug Development, 2020
Steven J. Nieto, Erica N. Grodin, Lara A. Ray
The role of genetics in AUD was founded on many years of observations that pathological alcohol consumption is clustered in families. Twin and adoption studies consistently find that the heritability of AUD is between 50% and 60% [14]; thus, transmission of risk alleles independent of environment may contribute to AUD etiology. While family, twin, and adoption studies provide initial evidence of an inherited risk of AUD, they cannot conclusively determine the role of genes in disease states. To address this issue, genetic linkage studies use a family-based method to evaluate whether one or more genetic markers spaced across the 23 chromosomes co-segregate with a disorder. The Collaborative Study on the Genetics of Alcoholism (COGA) was one of the first studies to utilize this novel genome-wide scan to map and characterize genetic variants that contribute to AUD [15]. With over nine research sites and an initial sample of 105 families and 987 individuals, COGA found that loci located on chromosomes 1, 7, and 3 linked with AUD, while different loci on chromosome 2 both linked with and were protective of AUD [16]. There are several limitations to linkage studies. For instance, these studies are labor-intensive because they require compilation of extended pedigrees. In addition, linkage studies offer poor genomic resolution because large chromosomal regions identified can contain several possible candidate genes.
Related Knowledge Centers
- Behavioural Genetics
- Schizophrenia
- Twin Study
- Heritability of Iq