By Rick Weiss
Washington Post Staff Writer
Thursday, June 14, 2007; A01
Washington Post Staff Writer
Thursday, June 14, 2007; A01
The first concerted effort to understand all the inner workings of the DNA molecule is overturning a host of long-held assumptions about the nature of genes and their role in human health and evolution, scientists reported yesterday.
The new perspective reveals DNA to be not just a string of biological code but a dauntingly complex operating system that processes many more kinds of information than previously appreciated.
The findings, from a project involving hundreds of scientists in 11 countries and detailed in 29 papers being published today, confirm growing suspicions that the stretches of "junk DNA" flanking hardworking genes are not junk at all. But the study goes further, indicating for the first time that the vast majority of the 3 billion "letters" of the human genetic code are busily toiling at an array of previously invisible tasks.
The new work also overturns the conventional notion that genes are discrete packets of information arranged like beads on a thread of DNA. Instead, many genes overlap one another and share stretches of molecular code. As with phone lines that carry many voices at once, that arrangement has prompted the evolution of complex switching, splicing and silencing mechanisms -- mostly located between genes -- to sort out the interwoven messages.
The new picture of the inner workings of DNA probably will require some rethinking in the search for genetic patterns that dispose people to diseases such as diabetes, cancer and heart disease, the scientists said, but ultimately the findings are likely to speed the development of ways to prevent and treat a variety of illnesses.
One implication is that many, and perhaps most, genetic diseases come from errors in the DNA between genes rather than within the genes, which have been the focus of molecular medicine.
Complicating the picture, it turns out that genes and the DNA sequences that regulate their activity are often far apart along the six-foot-long strands of DNA intricately packaged inside each cell. How they communicate is still largely a mystery.
Altogether, the new project shows that the simple sequence of DNA letters revealed to great fanfare by the $3 billion Human Genome Project in 2003 was but a skeletal version of the human construction manual. It is the alphabet, but not much more, for a syntactically complicated language of life that scientists are just now beginning to learn.
"There's a lot more going on than we thought," said Francis Collins, director of the National Human Genome Research Institute, the part of the National Institutes of Health that financed most of the $42 million project.
"It's like trying to read and understand a very complicated Chinese novel," said Eric Green, the institute's scientific director. "The take-home message is, 'Oh, my gosh, this is really complicated.' "
....
The reason these scientists are so surprised is that they believe that DNA evolved by strictly natural processes, such as random mutation and natural selection. The concept of "junk DNA" came directly from the theory of evolution.
When scientists first began looking at the genome, they noticed that only certain parts of the DNA code directly for proteins, the building blocks of cells. Other stretches of DNA seemed to be silent.
The evolutionary view was: "The silent "junk" parts are evolutionary left-overs from earlier ancestors, no longer needed."
The creationists' view was: "Since God designed DNA, and God is exceedingly intelligent, it's likely that this non-coding DNA has some other important function that we don't know about."
Imagine for a moment two intelligence officers being given identical copies of a few pieces of paper with a few hastily scrawled letters and numbers jumbled together. The two officers are separated into different rooms.
One analyst is told, "These papers were taken from the scrap paper pile in a first grade classroom. Check it out and let us know if there's anything important on it. If not, bring it back and we'll give you another sample to analyze."
The second analyst is told, "These papers was taken from the prison cell of one of the most devious and clever spies who ever lived, shortly after his death. The spy was also one of the world's best experts in steganography and information-theoretic ciphers. Check it out and let us know if there's anything important on it. If not, bring it back and we'll give you another sample to analyze."
It would not be surprising if the first person only gave it a quick glance while the second person spent weeks trying to analyze the code. That is exactly the current situation with DNA. Evolutionary scientists worldwide are suddenly scrambling to try to figure out the new coding schemes, having been thrown on the wrong track for decades by the theory of evolution. In fact, the theory of evolution may be one of the largest reasons that we do not yet have cures for many diseases.
Questions about how these amazing codes originated are being ignored for now.
It's an exciting time to be a biologist...
(cf. also my previous post about Dawkins' new book 
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