Cirque de Genome

DE RERUM NATURA - Maria Isabel Garcia () - March 15, 2012 - 12:00am

There’s a circus going on in your insides — lots of things breaking off from where they are supposed to be and going somewhere else and doing their thing. We have always thought that sure, life is like an improvisation play where there is a basic flow from the story passed on from generations and the turnout of the story would depend on audience’s reaction. But we did not know that there was a lot more action happening in our insides. No less than molecular acrobatics is going on inside and from the looks of it, it is what makes us truly unique from one another.

Fred Gage and Alysson Muotri are avid ringside followers of this unusual acrobatics show. Gage is a professor specializing in how neurons are generated in the brain at the Laboratory of Genetics at the Salk Institute for Biological Studies in California while Muotri is an assistant professor in the department of pediatrics and cellular and molecular medicine at the University of California, San Diego. Together, they wrote an article in the March 2012 issue of The Scientific American which riveted my attention. Entitled “What Makes each Brain Unique?” it basically explained through their findings that the genes that are supposed to be where they are when you begin as an embryo, are really doing quite a bit of jumping into other places in the genome and shaping who you are. And what’s more is that, the circus goes on well into adulthood and most of it happens in that part of the command area of the performing center — your brain.

This changes the whole nature of the show. Before this, we basically thought that nature, specifically about two percent or so of the 25,000 genes each human being was doing all their respective acts from their “stations” that determine your biological story. The rest, scientists have set aside as “junk DNA” or extras which then did not seem to have any important function. Then of course, “nurture,” how the environment will shape you, will flesh out the rest of what makes you, you. Now, Gage and Muotri have looked at genomes and concluded that some of those junk DNA have inserted themselves in other places in the genome, turning on genes that would otherwise have not been turned on had that “junk DNA” stayed where it was.

This is basically how it happens. Think of those limber dancing acrobats in Cirque du Soleil and imagine them in a scene where they are hanging in chains on different parts of the stage. First, during cell division as an embryo, part of one circus chain breaks off (DNA sequence) and copies itself into another kind of circus chain (RNA) which moves out of the center stage which is the nucleus into the cytoplasm. Next, that RNA portion translates the DNA sequence into new actors in a chain in the form of proteins which eventually joins the original RNA and other proteins. Then, they re-enter the center stage of the performance which is the cell nucleus. In the nucleus, RNA makes a copy of the DNA and inserts it in another place in the overall acrobatic chain on stage. With a “new” sequence beside it, a chain with its own role (gene) could be affected, changing the way the story is told. That is how the circus goes inside you.

But what makes those acrobats fly from their places and link with other chains? Gage and Muotri found that while this acrobatic performance happens in many places inside you, it mostly happens in the hippocampus, that part of the brain that is crucial to memory, and thus to learning. It is also that part where new cells are formed spurred when we learn something new. Gage and Moutri are entertaining the idea that perhaps what they call “jumping genes” are also triggered by new or unfamiliar settings. This makes perfect sense in that it further explains how nature is never done with its work the minute you are conceived and born. It still finds a way to make your “insides” cope with a changing environment and of course, there is no better way than to find the actors that could change the game and perhaps make for a better story of nature which is you.

Well, it is not always better. Nature’s alias is “luck” so that means, jumping genes could also make for things going awry and because they happen mostly in your brain, they may be responsible for schizophrenia and other brain stories that many struggle with. This is evidence that there is no grand design guiding nature to make humans biologically better — just a design to give you options to cope and if you are lucky, you just might.

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