Monday, June 06, 2016

Epigenetics

I've been writing every day and making good progress, but haven't had much time to put up blog posts along with that. I decided today what I'll start doing is putting up snippets of what I've been working on. Kill two birds with one stone, as they say. Yesterday I was writing about the phenomenon called "epigenetics." Here's a short introduction to it.

Epigenetics: Earlier, I said that even if two people ended up with exactly the same genes, that wouldn’t guarantee that those genes would work exactly the same way inside of them. How can that be? Well, it turns out that there is more interaction between your environment and your genetics than previously thought. The environment can change the way genes act, and once these changes occur, they can sometimes be passed on to offspring in the next generation. If that happens, it affects more than just the individual, it affects evolution.  

Epigenetics is not what Jean-Baptiste Lamarck considered “the inheritance of acquired characteristics,” although it may seem like it at first. For Lamarck’s idea to work, mutations would be needed in the DNA. Epigenetics—the “epi” means from outside—doesn’t cause a mutation in a gene. It doesn’t alter the way the DNA manuscript is written; it alters the way it is read. To say it another way, epigenetic events don’t add new information to our genome. They change the way that genome is expressed in a person. 

A number of epigenetic phenomena have been identified now. For example, in the “Hunger Winter,” the “Dutch Famine” at the end of World War II, thousands of people in the Netherlands starved as a result of Nazi occupation. Children born to pregnant mothers who suffered through this famine and lived have, as adults, shown higher rates of obesity and coronary heart disease than comparative control groups who did not experience starvation. How could this happen?

Well, to simplify, you have a lot of genes and not all of these are active at every given moment. Genes have, for want of a better term, “switches” that tell them when to turn on and when to turn off. Some genes are active during the fetal period but get turned off later. Other genes are inactive until they are turned on during the various stages of growing up and aging. In the normal course of a life, some genes may never be turned on. However, stressful events, such as the starvation people experienced during the Hunger Winter, can sometimes activate switches that wouldn’t normally be activated. This turns genes on or off, thus changing the way a person’s genome builds the structure of their bodies.

14 comments:

Alex J. Cavanaugh said...

So as a result of the starvation, the switch was thrown to pack in absorb every calorie possible, resulting in obesity when that wasn't needed anymore.

Charles Gramlich said...

Alex, that is the thinking. Still a lot to understand about this concept but that's it in a nutshell.

the walking man said...

The question that occurs is it primarily trauma in the environment that changes the genetic switching or does extended periods of pleasure, calm, peace have the same effect? Privation I am fairly certain limits the dopamine in the brain but what about the opposite during extended periods of positivity? Or does brain chemistry have nothing to do with the subject?

Charles Gramlich said...

Mark, brain chemistry is probably one of the triggers, although it's not completely clear. So far, all the epigenetic effects that I'm aware of have been triggered by stress. Interesting question about whether there could be positive triggers.

Prashant C. Trikannad said...

Charles, have you read Pulitzer Prize winning author Siddhartha Mukherjee's latest book "The Gene: An Intimate History"? I think you will like it. I read excerpts and found it absorbing. Mukherjee is on a "quest to understand human heredity and its surprising influence on our lives, personalities, identities, fates, and choices."

oscar case said...

The way medicine is advancing these questions may be answered before long.

sage said...

I knew you were engaging with academic writing instead of fantasy--interesting stuff you're working on this summer. I look forward to being educated from you posts!

Charles Gramlich said...

Prashant, no I haven't. Sounds like right down my alley, though. I'll have a look at it.

Oscar, one hopes.

Sage, thankee, man

Barbara Martin said...

Ah, science is intriguing in how it affects man in a multitude of ways. Thanks, Charles.

Riot Kitty said...

This is a fascinating subject for me! I'd like to read more about it.

Charles Gramlich said...

Barbara, glad you enjoyed.

Riot Kitty, it's a pretty new field of investigation but already lots of exiting things.

Cloudia said...

OH! Now I understand. You are and excellent teacher, C

Rachel V. Olivier said...

Huh. Interesting.

Charles Gramlich said...

Cloudia, thankee.

Rachel, yep, I think so.