It’s never been “junk” DNA. I seem to remember reading about this years ago, but it’s only made the news in a major way now, for some reason. Researchers working on the ENCODE project, which was begun to catalog all the pieces of the human genome — everything besides the genes themselves — have confirmed that about 80% of human DNA is regulatory in nature. That is, those bits of DNA don’t directly code for proteins that the body needs or uses.
As this Wired article puts it:
There are transcription factors, proteins that link these pieces together, orchestrating gene activity from moment to moment, and basic rules for that orchestration. There are also multiple layers of so-called epigenetic information, describing how the activity of genes is modulated, and how that varies in different types of cells.
And the proportion of these rules and regulatory elements to the actual genes themselves is quite stunning:
“Every gene is surrounded by an ocean of regulatory elements. They’re everywhere. There are only 25,000 genes, and probably more than 1 million regulatory elements,” said Job Dekker…
That’s a 40 to 1 ratio right there.
This information is crucial, because it’s often not enough to know simply which genes are expressed and which aren’t. Of course, the gene expression is often only the first step in a long process that results in a symptom or disease or hormone expression. But knowing only where the gene is and whether it’s turned on or off is akin to seeing only whether a a light switch has been thrown or not. You aren’t able to see the internal wiring or to control when and how that switch is thrown.
Hopefully, ENCODE will soon be able to give us glimpses of that wiring.
The Seventh Colour 