Thursday, September 06, 2012

Junk DNA: Regulating the genome

Several years ago when I was living in the charming little Swedish university town of Lund I walked over to the public library on a rainy day to read the latest edition of Scientific American. The cover article immediately snagged my attention with the authors' assertion that what had previously been thought of as junk sequences of DNA within the human genome were actually mechanism that regulate gene operations.

In other words there are chains of DNA that we call genes. These are periodically read, and then copied into RNA strands that in turn are used to manufacture the peptides (essentially tiny proteins) that are assembled into the building blocks, widgets, and other machinery of cellular life. Other non-coding stretches of DNA within our chromosomes--ones that had earlier appeared to be without purpose--had been studied and then looked as though they helped to regulate when and how and how often the genes are read and copied for use.

It was an exciting idea, and there was a nice symmetry in it. The notion that in increasingly complex micro and macro systems within our universe more and more internal regulatory mechanism are required to coordinate the timing of essential operations and the allocations of resources. Of course it was still early days for the idea that junk DNA played any kind of role. One study does not a scientific theory make.

Nearly a decade has passed between then and now, and a series of other studies have since confirmed the role of the non-protein producing segments as regulatory mechanisms. This confirmation gives us a much clearer picture of the human genome, and it's big step forward in learning how to read the body of computational data encoded in deoxyribonucleic acid that not only makes us what we are, but also plays a significant contributing role in determining who we are as individuals.


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