Because behavior genetics is a field defined by a common set of methods, regardless of topic there will be some conventions of data reporting that you will encounter over and over again in empirical (data analysis) papers.

This week we will:

  • Understand the logic and common applications of twin studies and GWAS.
  • Become familiar with standard formats of tables, graphs, and statistics commonly used in twin studies and GWAS.

Behavior genetics as a field is defined by the use of a common set of methods, usually based on the availability of genetically informative data, whether organized into known relative groups or having available genotype data or both. Because of this strong overlap in methods, once you understand the general properties of a method (what it tests, how we report results, what you can- or can’t- learn from it) you can begin to dive into the literature on any phenotype.

This week we will focus on what are probably the two most common current methods:

  • The Classical Twin Study, where we estimate the similarity (correlation) between identical twins, and the correlation between fraternal twins, on some phenotype of interest and draw conclusions on the basis of how those two correlations compare; and
  • The Genome-Wide Association Study, where we one-at-a-time test the correlation between each of millions of individual genetic variants with some phenotype of interest.

Both of these are rather broad analyses, involving a lot of simplification and resting on many assumptions. We tend to use both as a “first step” in understanding the genetics of a phenotype, and both can serve as a basis of or launching point for more niche, complex analyses that we’ll begin covering in-depth in Week 6.

Next: 4.1. How To Read A Twin Study

Previous: 3.2. Activity: Eugenics Journal Response

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