Imagine we could shrink down to itsy-bitsy versions of ourselves; so small that we are smaller than a cell, so small we could be mistaken for a molecule. Stepping into the rushing superhighway of your bloodstream, we spot a monocyte floating by. Snagging an epitope, we catch a ride on the monocyte, and dive through the lipid bilayer to see what’s beneath.
Inside the cell there is an incredible bustle of activity, with proteins running up and down actin filaments, dense granules soaking up the artificial light of our imagination, and looming in the center, surrounded by it’s own lipid bilayer, lies the nucleus. This is the goal of our journey, and swinging down a microtubule, we dive through a nuclear pore into the heart of the cell.
Here we see DNA in all of its slender double-helical glory, being wrapped tightly around histones. Suddenly, you see something remarkable. A DNA methyltransferase – an enzyme which does exactly as its name suggests – carefully transfers a methyl group to a specific region of DNA. The DNA, which had been loosely wrapped around the histones, coils tighter and becomes all but inaccessible.
You watch with rapt fascination as a DNA Polymerase bumps uselessly against the tightly bound DNA.
This is epigentics.
If DNA is the blueprint to every cell in your body, epigenetics is the foreman on the construction site deciding exactly what blueprints are relevant to his work site. The thing is, we have yet to come up with a way to become extremely small and peer into a cell, so unfortunately what we know about epigenetics is very limited. If you want a great (and relatively quick) review of what epigeneticw is, one of my favorite youtube channels covered it very well in this video.
You might say, well why is epigenetics important? Well let’s say you’re you, but you’ve only been around for 1 week. You’re developing in your mother’s womb, and your cells are multiplying and dividing, as they are wont to do.
Those cells will eventually become heart cells, skin cells, brain cells – all the various cells that make up the entity that is you. Epigenetics is what directs those cells to differentiate into a specific cell. It’s the foreman looking at the blueprints and yelling “alright boys! This one’s a neuron! Let’s get those dendrites sprouting!”
In a time when genetic sequencing is cheap enough for the layperson and 3D modeling of protein interactions is within our grasp, here lies an entire field of biology that has barely been scratched. Most researchers study epigenetics through another lens: genetic, proteomic, clinical, etc. The genetic lens is, like I said, akin to looking at blueprints and imagining how the tower can be built from them. The proteomic lens is like looking at the tower and trying to figure out how they managed to fit it all together. Sometimes, I think, scientists would do well to simply listen to the foreman- he knows exactly how those blueprints became that tower.