Front end loading (Introduction)

by George Jelliss , Crewe, Saturday, November 15, 2008, 19:37 (5638 days ago) @ David Turell

Yes, I found that article fascinating. But it doesn't seem to me to show the DNA/RNA system to be "complex" in the sense of being designed. It shows just how chaotically "undesigned" it is. Engineers would not design a machine in which one component "drags along unnecessary excess baggage" or which gets contaminated by the "rotting carcases" of extraneous interlopers! - Here are some quotes from the article: - David Haussler, another Encode team member at the University of California, Santa Cruz, agrees with Dr. Birney. "The cell will make RNA and simply throw it away," he said. - Dr. Haussler bases his argument on evolution. If a segment of DNA encodes some essential molecule, mutations will tend to produce catastrophic damage. Natural selection will weed out most mutants. If a segment of DNA does not do much, however, it can mutate without causing any harm. Over millions of years, an essential piece of DNA will gather few mutations compared with less important ones. - Only about 4 percent of the noncoding DNA in the human genome shows signs of having experienced strong natural selection. Some of those segments may encode RNA molecules that have an important job in the cell. Some of them may contain stretches of DNA that control neighboring genes. Dr. Haussler suspects that most of the rest serve no function. - "Most of it is baggage being dragged along," he said. - --- - "Our genome is littered with the rotting carcasses of these little viruses that have made their home in our genome for millions of years," Dr. Haussler said. - --- - These new concepts are moving the gene away from a physical snippet of DNA and back to a more abstract definition. "It's almost a recapture of what the term was originally meant to convey," Dr. Gingeras said. - This is another good example of the way scientific research moves on. Older over-simplified ideas get discarded in light of new information.