Epigenetic Basis for Behaviour

On Thursday, we had a very interesting lecture in my Biol-516 class (Genetics of Mammalian Development) on the epigenetics of behaviour. For those of you not in the know, I'll do a little background first (for the Bio students, however, this will be severely dumbed down so you can probably skip this entry).

Epigenetic refers to something that affects a cell without directly affecting its DNA. An epigenetic change may affect the expression of the genome, ie: the phenotype (what you see as a result of the genes). The epigenetic basis for behaviour therefore refers to the nongenetic effects on the phenotype that is behaviour.

The professor who presented this material was doing work on rats and was interested in the pharmacological aspects of the research. His work consisted of studying rats who exhibited a behaviour called "licking," where a mother rat would lick its progeny and thus affect the behaviour of those offspring. The mothers were divided into two categories: high lickers (HL) and low lickers (LL). The HL mothers produced progeny who would also become HL. The LL mothers would produce progeny who would become LL. At first glance, this looks to be an inherited trait, a parent displays a phenotype and its progeny display a similar phenotype. To test this, the researchers then cross-fostered the progeny. Offspring from HL mothers were given to LL mothers, and vice-versa. At this point, HL mother offspring now with LL mothers became LL. The opposite also held true (LL offspring with HL mothers became HL). It would seem then that this is no longer a heritable trait, but rather one influenced by the behaviour (phenotype) of the parent.

On preliminary inspection, this is not unbelievable. Orphaned siblings raised by different foster parents will often adopt the behaviours of those parents. A closer look at the cellular process behind the licking phenotypes revealed the molecular basis. Licking by the mothers seemed to stimulate an endocrine (hormonal) response. Serotonin is released, initiating its pathway to a protein which I will, for simplicity, call the "licking protein". When manipulated with the use of a drug, the researchers were able to control the behaviour of the progeny, independent of the actions of the mother. In short, behaviour modification through the use of drugs.

You may be wondering why I'm presenting this information to you. The reason for it is this, if there is a "licking protein" (and thus, a "licking gene" as all proteins are the result of genes) could there not perhaps also be an "aggression gene"? And if so, could we control it? What if we were able to delete these genes without adversely affecting the rest of the genome? Would we then have a solution for all the murderers, rapists, and abusive people out there? I suppose it's possible. Years ago, it was inconceivable that cloning might actually be possible, and look now it's become a science project that has captured the attention of the world.

What we need to be thinking about is the ethical basis for such work. Who would benefit from the results? How might the government use this information? What are the legal aspects of this work? Unlike Genetically Modified Organisms, or GMOs (ie: "Golden Rice"), these procedures could have serious repercussions to the Human Rights Movement. And yet, this is valuable information for those looking to cure themselves of behaviours which might otherwise condemn them to life in prison, or worse. Parents might then be able to screen the DNA of their children for genetic defects, things like overexpression of possible aggression genes. Rather than spend a lifetime popping pills to suppress such urges, why not simply attack the problem at its source? Nip it in the bud, as my friends might say.

Despite the negative consequences of such work, I support the further investigation of our DNA and genomes. Curiosity drives so many of us, academic or otherwise, why suppress the need to know more? Why, without curiosity or a will to go that extra step, we would never be as technologically advanced as we are. Our current level of science permits us to manipulate the world around us. It has given us the ability to cure diseases once thought to be incurable. We can study the evolution of the Universe. Hell, we can even draw pictures with atoms by moving them around one at a time! (Ok, so that last one is not so useful, but it's still amazing.) Some would argue that it's not our place to "play God", manipulating life and matter around us. But until we find evidence for God, why should He have control over our actions? As was proven by the Evolution vs Creationism trials, religion has no place in science. If you're going to use religion as a defense, then do it with issues like sins and the like. Don't bring it into the lab because it will get you no where. But I digress...

My ultimate goal here is to stimulate discussion of the ethics behind this kind of work. Through dialogue, we may yet find a direction for this research and, hopefully along the way, create some guidelines that don't restrict what I would call Human Nature.