Twin Studies in Behavioral Genetics

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What are potential consequences of more similar treatment of MZ twins in relation to DZ twins in twin studies?

Increased MZ correlations relative to DZ correlations, overestimating genetic effect and underestimating shared environmental effect.

How can differential prenatal history of MZ versus DZ twins affect the classical twin study?

It may lead to differences in monochorionic and dichorionic MZ twin pairs, challenging the validity of the classical twin study.

What is the main purpose of SEM methodology in twin data analysis?

To partition genetic from environmental factors on a trait.

How can SEM methodology be extended to address limitations in twin studies?

By testing sex differences and modeling measurement errors. Signup and view all the answers

What is the classical twin design primarily used for?

To partition genetic from environmental factors on a trait. Signup and view all the answers

What are the implications of potential violations of the EEA in twin studies?

Biased estimates of genetic and environmental effects. Signup and view all the answers

What is the purpose of calculating the pairwise concordance rate in twin studies?

Now obsolete Signup and view all the answers

Why is an ascertainment correction needed in proband-ascertained twin samples for structural equation modeling?

To correct for the distortion in frequencies caused by ascertainment Signup and view all the answers

How can the cell probabilities in a contingency table be adjusted for ascertainment correction?

By introducing an ascertainment probability for each cell Signup and view all the answers

Which software can be used for maximum-likelihood analysis of categorical data from proband-ascertained samples?

Mx Signup and view all the answers

What assumption is made regarding the shared environment in MZ and DZ twins in the twin method?

Equal environments Signup and view all the answers

What does a difference between MZ and DZ concordance rates suggest in twin studies?

Genetic component to the disorder Signup and view all the answers

How can the assumption that twins are representative of the general population impact the estimation of heritability?

It can lead to an underestimation or overestimation of the heritability of the trait. Signup and view all the answers

What is one way to detect if twins are not representative of the general population?

Compare the prevalence of the trait in twins and singletons. Signup and view all the answers

What is the purpose of power studies in the context of twin research?

To determine the sample size needed to obtain a reasonable estimate of genetic influence on a trait. Signup and view all the answers

How many pairs are typically needed for power studies to estimate the degree of genetic influence on a highly heritable trait?

At least 200 pairs. Signup and view all the answers

What assumption does the Classical Twin Design make about environmental similarity for both types of twin pairs reared in the same family?

Equal environments assumption (EEA). Signup and view all the answers

What can lead to an overestimation of the shared environmental effect in twin studies?

Different genotypes responding differently to the same environment. Signup and view all the answers