Thursday, 13 September 2012

Junk Stories about Junk DNA

From here:

Unfortunately, things like well-established facts make for a lousy story. So instead, the press has often turned to myths, aided and abetted by the university press offices and scientists that should have been helping to make sure they produced an accurate story.
Discovery of new regulatory DNA isn't usually surprising, given that we've known it's out there for decades. There has been a steady stream of press releases that act as if finding a function for non-coding DNA is a complete surprise. And many of these are accompanied by quotes from scientists that support this false narrative.
The same thing goes for junk DNA. We've known for decades that some individual pieces of junk DNA do something useful. Introns can regulate gene expression. Bits of former virus or transposon have been found incorporated into genes or used to regulate their expression. So some junk DNA can be useful, in much the same way that a junk yard can be a valuable source of spare parts.
But it's important to keep these in perspective. Even if a function is assigned to a piece of junk that's 1,000 base pairs long, that only accounts for about 1/2,250,000 of the total junk that is estimated to reside in the human genome. Put another way, it's important not to fall into the logical fallacy that finding a use for one piece of junk must mean that all of it is useful.
Despite that, many new findings in this area are accompanied by some variation on the declaration that junk is dead. Both press officers and scientists have presented a single useful piece of virus as definitively establishing that every virus, transposon, and dead gene in the human genome is essential for our collective health and survival.

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