Epigenetic Modifications Are Affecting the Way We Think

By admin on February 17, 2015

The Nature vs. Nurture Debate

The question of whether behavior, or an aspect of behavior, is primarily dictated by genetics or by environmental experience has been a longstanding debate. ‘Nature’ and ‘Nurture’ have been viewed as mutually exclusive poles. Although historically, scientists believed that the genetic information we inherited from our parents was fixed in our DNA sequence, we now know that environmental factors can alter the genome in multiple ways.

Epigenetics: The Interface Between the Environment and Genetics

Environmental factors such as toxins and radiation can cause mutations in the DNA sequence including deletions, insertions, and single nucleotide substitutions. More recently, it has been recognized that environmental cues can modify DNA in ways that do not directly alter the DNA sequence. These are called epigenetic modifications. The field of epigenetics probes the interface between environmental experience and genetic adaptations.

There are over 40 types of epigenetic modifications. The addition or removal of chemical groups to the nucleotides that make up the DNA can affect whether a particular gene is available to be read. For example, the addition of a methyl group to a cytosine nucleotide will lock a gene into the “off” position, prohibiting the gene from being read. Epigenetic modifications can also be made to histones, the proteins that help to pack and organize DNA within the nucleus. Ultimately these modifications dictate if, when, and how much a gene is transcribed.

Epigenetic modifications, which occur in nearly all cell types of the human body, are responsive to environmental stimuli, including toxins, stress, and learning. These modifications can be stable, long lasting and heritable; however, most are known to be dynamic and reversible processes. A burgeoning field of research in behavioral and social sciences is the study of epigenetic modifications occurring in the brain, in neurons, known as neuroepigenetics.

Neuroepigenetics

Neuroepigenetics research is focused on studying this link between environmental factors, the brain, and behavior. For example, early maternal care may produce neuroepigenetic modifications that enhance the brain’s ability to adapt which, in turn, primes the brain for improved learning throughout life. In this way, neuroepigenetics bridges the gap between the two sides of the nature vs. nurture debate.

Neuroepigenetics, including regulation of gene expression and chromatin structure, plays an important role in normal brain function. Studies have shown the importance of neuroepigenetic regulation in neuronal development, neuronal plasticity, stress responses, learning and memory, and aging. Neuroepigenetic modifications have also been implicated in various pathological processes, such as post-traumatic stress disorder, Alzheimer’s Disease, Schizophrenia, and neurodevelopmental disorders, such as Autism Spectrum Disorder and Rett Syndrome. Overall, a better understanding of neuroepigenetics will lead to both a better understanding of learning and behavior and better treatments for learning disabilities and mental disorders.

Upcoming Lecture

Join us on March 13, 2015 as OBSSR presents “Epigenetic Mechanisms in Memory Formation,” a lecture by Dr. J. David Sweatt of the University of Alabama, Birmingham. Dr. Sweatt is an expert in the field of neuroepigenetics whose work focuses on signal transduction mechanisms in learning and memory.

Title: Epigenetic Mechanisms in Memory FormationSpeaker: J. David Sweatt, Ph.D., University of Alabama, Birmingham
Date: Friday, March 13, 2015
Time: 2:00pm – 3:00pm
Location: Natcher Conference Center, Balcony B, NIH Campus, Bethesda, MD