Behavioural Genetics Interactive Modules

An online introduction to BG research

Shaun Purcell, 2000.
WWW demos
Correlation & Regression
Single Gene
Variance Components
Extremes Analysis
QTL Mapping

Download all modules (ZIP)

For information on how to use the modules, please follow the link by clicking on the symbol to the right.

This module is designed to introduce the concept of variance: what it represents, how it is calculated and how it can be used to assess individual differences in any quantitative trait. Standardised scores are also introduced.


How the covariance statistic can be used to represent association between two measures is introduced in this module.


Correlation & Regression
The Correlation & Regression module explores the relationship between variance, covariance, correlation and regression coefficients.


Matrices provides a simple matrix calculator.


Single Gene Model
Single Gene Model introduces the basic biometrical model used to describe the effects of individual genes, in terms of additive genetic values and dominance deviations.


Variance Components : ACE
Variance Components: ACE illustrates the partitioning of variance into additive genetic, shared environmental and nonshared environmental components in the context of MZ and DZ twins.


Families demonstrates the relationship between additive and dominance genetic, shared and nonshared environmental variance and expected familial correlations for different types of relatives.


Model-fitting 1
Twin covariance matrices are modelled by manually adjusting the components of variance in order to find the best-fit parameter estimates for ACE model; nested models can then be compared to the full ACE model.


Model-fitting 2
This on-line resource performs a maximum-likelihood analysis of univariate twin data and presents the parameter estimates for nested sub-models. The tutorial explains how to use the module and how to interpret the output.


Multivariate Analysis
Multivariate Analysis models the genetic and environmental aetiology of two traits.


Extremes Analysis
Extremes Analysis illustrates how DeFries-Fulker extremes analysis can be used to estimate components of variance from twin data by looking at extreme-scoring individuals and their co-twins.



Miscellaneous BG Resources

Introduction to Mx
This provides a basic introduction to the Mx model-fitting package.
Beginning Quantitative Genetic Analysis
Four tutorials introduce basic quantitative genetic analyses, using commonly available statistics software such as Stata and SPSS. Several of the modules are also used, as is Mx. Various simulated datasets are presented as well as commentary on the methods of analysis and results.
This on-line resource allows users to easily simulate multivariate ACE datasets and explore the properties of the Cholesky decomposition description of data.
Maximum Likelihood Estimation
This on-line tutorial introduces an area central to the model-fitting approaches described here: maximum likelihood estimation.
Linkage & Linkage Disequilibrium
This on-line tutorial and module aims to introduce the related phenomena of linkage and linkage disequilibrium.

Probability Calculator
This on-line resource allows the easy calculation of probability functions such as the chi-squared and normal distributions, replacing the need to look up significance values in tables.
Twin Zygosity Calculator
Determine whether a twin pair is identical or not with this on-line questionnaire.
Under Construction
  • Reading Lists, provided as a starting point for individuals wishing to pursue their interest in behavioural genetics further.
  • Electronic Glossary, an electronic glossary to cover most of the terms used in the Behavioral Genetics text.
  • World Wide Web Links, a selection of what the WWW has to offer in terms of genetic and statistical resources.

About this site
Site created by S.Purcell, last updated 27.10.2000