Classical twin studies compare identical twins, who share all genes, to fraternal twins, who share about half. This allows researchers to distinguish the effects of genes versus environment on traits. Researchers collect DNA data, measures of cognitive and physical characteristics, and environmental factors from twins. They study topics like substance use, executive function, adolescent development, and psychopathology to understand the relative contributions of nature and nurture.

1. Twins and Research in Behavioral Genetics
What is Behavioral
Genetics?
Behavioral Genetics is the
research on the genetic and
environmental bases of
individual differences in
behavior.
Why Use Twins?
• Classical twin studies look at twins
raised in the same family environments.
• Identical twins share all of their genes,
while fraternal twins share only ~50% of
the different genes they get from their
parents.
• So, if a researcher compares the
similarity between sets of identical twins
to the similarity between sets of
fraternal twins for a particular trait, then
any excess likeness between the
identical twins should be due to genes
rather than environment.
Types of Data Collected:
DNA
Cognitive Functioning:
-Behaviors/mood and conduct disorders
-Executive function
-Intelligence/academics
-Mental health
Physical Characteristics:
-Height -Weight -Appearance
-Gender -Microbiome
Environmental Measures:
-Location -Friendships
-School district characteristics
Areas of Study:
-Substance Use
-Executive Cognitive Functioning
-Adolescent behavior and development
-Early reading development/disabilities
-ADD/ADHD
-Personality
-Psychopathology
By collecting these different types of data, researchers can begin to tell differences between effects of nature (genetics) and nurture
(environment). Each one of us is the result of the joint contributions of our genetic background and our environment.
For more information on twin research carried out by CU, please visit http://www.colorado.edu/ibg/
Fun Fact:
The bacteria in your body (called the
microbiome) make up 90% your cells.
Researchers are studying how similar twins are
in terms of these bacteria! Guess how this data
is collected?
Nature vs. Nurture