Methylating the Mind

All brain cells are the same, genetically speaking. Yet somehow they play vastly different roles, some directing movement, others participating in language or thought. Now, a study finds that a chemical known to turn genes on and off may be partially responsible for this division of labor. The results, researchers suggest, could help scientists better understand psychiatric and neurological diseases.

It takes more than genes to make people who they are. Identical twins, for example, can look and act differently even though they share the same DNA (ScienceNOW, 5 July 2005). Environmental factors likely contribute to this variation, but it also seems to depend on so-called epigenetic phenomena, activity that regulates genes without changing the DNA code (ScienceNOW, 12 April 2006). In the 1960s, researchers found that the addition of a molecule called a methyl group to cytosine, one of the four building blocks of DNA, could turn off genes. Since then, scientists have found that this process, called methylation, can also turn genes on and that it is linked to cancer (ScienceNOW, 31 January 2000) and short-term memory formation (ScienceNOW, 14 March).

Because no studies have surveyed methylation's role in assigning marching orders to brain cells, geneticist Andrew Feinberg and psychiatric neuroscientist James Potash, both of Johns Hopkins University in Baltimore, Maryland, decided to investigate. Along with their colleagues, they compared possible methylation sites on 807 genes in 76 samples from human brains. Among the regions studied were the cerebellum, which controls movement, and the cerebral cortex, which controls language and memory. The team found that methylation patterns differed by brain region, indicating that epigenetics helps divide up the brain's functions. These patterns proved more robust than differences in methylation linked to race, age, or sex, the team reports in the December issue of The American Journal of Human Genetics.

The study makes clear, Feinberg says, that "working on the brain without thinking about epigenetics is like working with a blindfold on." By understanding normal methylation, he adds, researchers can begin to look at methylation gone wrong, possibly in autism, depression, bipolar disease, and schizophrenia.

Given that epigenetics has been shown to modify gene expression in other parts of the body, the brain results are not surprising, says psychiatrist Schahram Akbarian of the University of Massachusetts Medical School in Worcester. "One could say neuroscience is catching up with the rest of the field."

Now reading this article about "methylation", well what happens in the intestines...? You get methane gas. So that is even more proof of a connection.

I believe the difference and similarity between the brain and the intestine is like this: The intestine takes food and processes it into proteins and nutrients that sustain life. While the brain takes information and process that to thoughts so the human can get ideas on ways to consume more food... and thus there is a cycle there.

In the intestine you get methane gas (you know, farts) but in the brain you get thoughts and ideas that seem to bubble up. That sounds funny but still we are talking about "methylation and methane and some expert should look into that. It's only going into 2008 and I got to be the one to point this out. And if I'm going to be flamed at least be funny about it.

I am not a "medical expert" but as a person with a brain it always seemed to me that when you look at the human anatomy in regards to the brain, you can see that the brain is connected via the throat to the intestinal tract and that the two actually do look similar and the brain is a muscle like the intestines.

You're arguing on the basis of analogy, a fallacy. You could claim that "methyl" is 5/6 a friend of Lucy Ricardo. You may as well try to draw conclusions about reproduction between squirrels, Home Depot, politics, and pornography because at one point or another they all have something to do with nuts.

The brain is not a muscle. The two don't look similar beyond the superficiality of what appears to you as convolutions. In the intestines this is due to the packing of a tube. In the brain, which is not a tube, the convolutions have the function of increasing surface area, which increases the number of particular sorts of neurons.

Who doesn't know about the similarity between methylation and methane? Methane is a gas formed of single carbon atoms each with four hydrogens. A methyl group is a single carbon atom with three hydrogens attached to another molecule.

DNA Methylation involves the attachment of that methyl group to a location in DNA. When it's there, the DNA polymerase can be prevented from reading through the DNA. Think of it as a concrete police barricade thrown up across an otherwise open thoroughfare. When doing sequencing in the lab we sometimes have to do a bisulfite reaction to get the polymerase to read through that block in order to be able to see the whole sequence.

Differing levels and types of DNA methylation in different tissue types and subtypes are thought to be regulatory mechanisms that limit gene expression to produce an array of proteins chemical substances appropriate for a specific type of tissue or function. After all, who would want the genes for producing hydrochloric acid pumps or digestive enzymes to be active in neural tissue? Think of methylation as one of the ways the body has of restricting the information in DNA to what is site-appropriate.

De-methylation is a chemical process, not a medical treatment for repairing improperly methylated DNA, though it's sure to appear in a quack medicine website somewhere.

PBS Nova had a thing on this. The ‘epigenome’ seems interesting, and manipulating it might be easier than changing the actual genome, so there might be some new treatments for diseases with the epigenome before some with the genome.

Yes. Ghost in your genes

If some treatments can be discovered, there will be less human suffering (and fewer abortions based on genetic testing).

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