In one experiment, strain B6 mice males were carried and raised by mothers from the Balb strain. The mothers of the Balb strain were transferred B6 embryos during prenatal development. B6 mice carried and raised by Balb mothers acted more similarily to Balb mice than B6 mice in regards to anxiety levels and maze times. This indicates that the different behaviors of B6 mice must be due to prenatal environments and postnatal experiences in addition to genetics.

Epigenetic Effects on Mouse Behavior

Methylation is the chemical modification of DNA that does not affect the nucleotide sequence of the gene itself, but makes the gene less likely to be expressed. 

Methylation 

-immediate early genes: genes expressed briefly by almost any neuron that has been stimulated.

-Lights, odors, and touches will affect neuronal expression of immediate early genes in specific regions of the brain as well as other regions that receive sensory information. 

Epigenetic Regulation in Adults

Epigenetics involves genetic control by factors other than an individual's DNA sequence. Epigenetic changes can switch genes on or off and determine which proteins are transcribed. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.

Epigenetic Influence

The study of gene-environment interactions, such as how the same genotype leads to different phenotypes. It studies heritable chemical modifications to DNA that alter gene activity without making alterations to the nucleotide sequence of genes themselves.

Columbia University

University of Michigan - Ann Arbor

Experience and the environment regulate gene expression in brain development by helping to shape behaviors and a person's surroundings and vice versa. This is called epigenetics.

Genes and Experience Guide Brain Development

* Range of reaction 
* Genetic environmental correlation
* Epigenetics

Perspectives on Gene-Environment Interactions

American Psychological Association. (n.d.). APA Dictionary of Psychology. American Psychological Association. Retrieved from https://dictionary.apa.org/ 

APA Dictionary of Psychology

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

Epigenetics

Range of Reaction is the theory that each person responds to the environment in a unique way based on their genetic makeup. According to this theory, an individual's genetic potential is a fixed quantity. However, whether an individual reaches their full intellectual potential depends heavily on the environmental stimulation they experience, particularly during childhood.

Range of Reaction

Genetic environmental correlation is a perspective on gene-environment interactions suggesting a bidirectional relationship between an individual's genes and their environment. This concept posits that not only do genes and the environment interact, as in the range of reaction theory, but they also mutually influence each other. In essence, our genetic makeup can shape the environments we are exposed to, and those environments, in turn, affect the expression of our genes.

Genetic Environmental Correlation

The epigenetic perspective offers a very different view of gene-environment interactions compared to the range of reaction. In the range of reaction model, a person's genotype is viewed as establishing fixed, limited boundaries for potential development. In contrast, epigenetics asserts that the genotype is not rigidly fixed and limited; instead, environmental factors can flexibly alter how the same genetic information is expressed into different phenotypes over time.

Comparison of Epigenetics and Range of Reaction

A critical approach to understanding schizophrenia involves examining research findings on the disorder through the lens of various gene-environment interaction models. This analytical process helps determine which perspective, such as range of reaction, genetic environmental correlation, or epigenetics, provides the most comprehensive explanation for the evidence.

Applying Gene-Environment Interaction Models to Schizophrenia

Read the following scenario. Analyze the story by identifying and explaining one clear example for each of the three distinct ways that genetic predispositions and environmental factors can interact to shape an individual's traits and behaviors.

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