EPIGENETICS

By: Teddy Bernal

Overview

Epigenetics studies how environmental and behavioral factors can alter our genes. Epigenetics differs from regular genetic changes, as epigenetic changes are reversible. This is because epigenetics do not alter DNA sequences; instead, they alter how an individual’s body reads the DNA sequence. This is important because it shows that environmental and lifestyle factors can influence gene expression throughout an individual lifetime.

Epigenetics’s Affect on Gene Expression

DNA Methylation is an example of an epigenetic change. It is when a chemical group is added, usually to specific parts of  DNA. This group of chemicals blocks the proteins that read the genes in our DNA. This means that methylation influences our genes by essentially “turning them off.” This is significant because the expression of specific genes may not occur as a result of methylation. While methylation makes genes turn off, the opposite can happen with demethylation, the process of turning genes on. This means that the expression of a gene can occur due to demethylation.

Similar to methylation, DNA acetylation is another form in which epigenetics affects gene expression. In acetylation, additional acetyl groups are added to specific proteins. One protein that this process usually occurs in is histones (proteins responsible for the formation of chromatins). This means that acetylation is a method where chromatin structure can be altered. This structure change can influence gene expression, as it can either loosen or tighten the chromatin structure. This affects gene expression, as the tightening of the structure can lead to gene repression, while the loosening of the structure can lead to gene activation.

Although there are various significant forms in which Epigenetics can alter gene expression, one last major one is environmental influences. Our environment plays a crucial role in epigenetic modifications. For example, factors such as our diet, stress, and chemical/toxin exposures can significantly influence how our genes are expressed, as it can lead to modifications in processes such as methylation. Since methylation affects how our genes are expressed, our environment can influence these changes.

Citations 

-1. P. Gujral, V. Mahajan, A. C. Lissaman, A. P. Ponnampalam, Histone acetylation and the role of histone deacetylases in normal cyclic endometrium – reproductive biology and endocrinology. BioMed Central (2020), (available at https://rbej.biomedcentral.com/articles/10.1186/s12958-020-00637-5#:~:text=Histone%20acetylation%20is%20a%20critical,cell%20cycle%20progression%20and%20differentiation.). 

-. B. Weinhold, Epigenetics: The science of change. Environmental health perspectives (2006), (available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1392256/). 

-. What is epigenetics? Centers for Disease Control and Prevention (2022), (available at https://www.cdc.gov/genomics/disease/epigenetics.htm#:~:text=Epigenetics%20is%20the%20study%20of,body%20reads%20a%20DNA%20sequence.).