Epigenetics – What does it tell us?
As an organism grows and develops, chemical reactions activate and deactivate parts of the genome at specific locations at critical times. Epigenetics is the study of these chemical reactions and the factors that influence them. Here is a great video that outlines the basic principles of Epigenetics: http://learn.genetics.utah.edu/content/epigenetics/intro/
Why is epigenetics important?
It goes against the idea conventional thought that inheritance only happens through the DNA code that passes from parents to offspring. A parent’s experiences can be passed down to future generations.
As you know, most organisms develop from reproductive cells: eggs and sperms in animals. Basic biology here – two reproductive cells meet, then grow, and then divide to form every possible cell type in the adult organism. For this process to occur the epigenome has to be erased through “reprogramming”.
In this “reprogramming” process the eggs and sperm develop from specialized cells where their genetic information is tagged with epigenetic markers. These markers are erased before the embryo develops.
For a small group of genes the epigenetic markers survive through this process and pass unchanged from parent to offspring.
In rat pups, high or low nurturing from the mother develops epigenetic differences that effect their response to stress later in life. When these female pups become mothers themselves, the ones that received high nurturing provided high nurturing to offspring, and those that received low nurturing provided low nurturing to their offspring.
So what does this all mean?
Epigenetic inheritance adds another aspect to evolution. It may also allow an organism to adjust its gene expression to fit its environment, without changing its DNA code.
This sheds light on the fact that our environment and experiences can adjust our gene expression and be passed down to our offspring.
Overall, we need more information on what the full role of epigenetics is and how it affects us, especially through generations.