Epigenetics, as it’s name implies is a collection of genome wide alterations that would change the information that is coming out of the genome, without changing the sequence. These changes are heritable from cell division to cell division, and in some cases from parent to offspring. This idea sounds a bit odd the first time around. We get used to thinking about mutation as one of the few ways that gene information can be changed in a heritable way, but it turns out there are more. Biology is smart, or at least it has had allot of time to figure out how to get things done.
As a field toxicology is concerned with the way that the environment effects living organisims and one area of interest has always been genotoxic compounds. Epigenetics adds a new dimension to this as epigenetic changes cause alter gene expression and if you look for examples there are plenty of mechanical changes in the genome of cancer cells that part of the epigenetic machinery. Toxicologist are very interested in what xenobiotics would be involved in altering epigenetic patterns.
Finally there is one more twist that is worth mentioning. I like all biologist of my time grew up thinking of the world using Darwin‘s evolutionary paradigm. There was another contemporary of Darwin that many of us have heard about that is often used as a counterpoint to stress how other scientists of the time thought of change that occurred across species. The cartoon that I can still remember to this day is Jean-Baptiste Lamarck‘s giraffe stretching to eat the leaves higher and higher in the tree. Ridiculous! But wait, epigentics proposes a model by which the environment might actually be able to influence the genome of an organism and produce heritable changes in gene expression. This may not be what Lamarck was thinking of, but it does sound eerily similar.
The toxicology paper is a good review of epigenetic mechanisms and it has a few “gee-wiz” biology examples.. There are however many practical examples of how epigenetics works, and diseases that may have an epigenetic component. I have asked the Tox 1401 students to head on over to OMIM and search using the term “epigenetic”, to find some examples. Look through the comments to see what they have come up with.