The Internal Mechanisms
An article in the National Post looks at the latest advances in understanding the human genome, that is, decoding the mechanisms of gene expression or how genes turn on and off. Each human contains about 20,000 genes, which are considered the instructions for life. But since genes comprise only about 2 percent of DNA, and most of the DNA lies outside of genes, it's important to know what is happening with the other 98 percent.
The findings, reported Wednesday by more than 500 scientists, reveal extraordinarily complex networks that tell our genes what to do and when, with millions of on-off switches. “It’s this incredible choreography going on, of a modest number of genes and an immense number of … switches that are choreographing how those genes are used,” said Dr. Eric Green, director of the National Human Genome Research Institute, which organized the project.
The work also shows that at least 80% of the human genetic code, or genome, is active. That’s surprisingly high and a sharp contrast to the idea that the vast majority of our DNA is junk.
Most people know that DNA contains genes, which hold the instructions for life. But scientists have long known those genetic blueprints take up only about 2% of the genome, and their understanding of what’s going on in the rest has been murky.
Similarly, they have known that the genome contains regulators that control the activity of genes, so that one set of genes is active in a liver cell and another set in a brain cell, for example. But the new work shows how that happens on a broad scale.This information is more than pure academic interest; the knowledge these scientists gain will go a long way to eventually eliminating many diseases that now debilitate us. We are now beginning to understand better what happens at the genetic level; thus, the more knowledge of how our genes work the greater we can eventually understand the genetic mechanisms that cause diseases such as diabetes, asthma and cancer, and why some people are more prone to heart disease and hypertension.
And, as is common with giant advances in understanding, textbooks will have to be rewritten to better define genes, the National Post writes: "Another finding raises questions about just how best to define a gene, researcher Thomas Gingeras of the Cold Spring Harbor Laboratory in New York and colleagues suggest in their report in the journal Nature. The common notion that genes are specific regions of DNA that are separated from other genes “is simply not true,” he said. Scientists are finding out that this is not necessarily true and is more related, in the language of genomics, to "functional products."
You can read the rest of the article at [National Post]