SCIENCE: Complete Human Genome Published Today
What was released previously to great fanfare was a working draft. This is the real deal.
"The working draft allowed researchers to kick-start a multitude of biomedical projects. Now they have a highly polished end product, which will assist them even more. It's a bit like moving from a first-attempt demo music tape to a classic CD." [1]
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"What we've got now is what we'll have for all eternity," says Francis Collins, director of the US National Human Genome Research Institute and the head of the consortium of 16 international institutions that collaborated to sequence the code. [1]
Now, there are no substantial holes left in the string of three billion base units that make up our chromosomes and determine our biology. There are still parts that are technically unsequenceable, says Collins, "but it's only about 1.5 per cent. That's what we called the finishing line when we began this enterprise, and now we've actually done it." [1]
I have to wonder about the 1.5 that's technically unsequenceable. Is this the so-called "junk DNA" I've heard about? Another interesting fact (and humbling) fact came about as a result of this research: apparently our entire DNA sequence reveals we have far fewer genes than expected.
While past estimates varied up to 140,000, two international scientific teams have now shown the true number is between 27,000 and 40,000. The finding deals a heavy blow to genetic determinism, the idea that many aspects of a person's life are controlled by their genes. [2]
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Equally striking is our vast collection of "junk" DNA. Genes turn out to fill just 1.5 per cent of our chromosomes while repetitive copies of "jumping genes", or transposable elements, claim about half our DNA real estate. Other species seem to clear away this debris more easily. Only three per cent of the fruit fly's genome consists of such sequences. [2]
Another interesting fact: we have apparently inherited 223 genes directly from bacteria, and many of these pay vital roles in sustaining life as we know it. The gene transfer must have occurred when wayward bacterial DNA integrated into the sperm or egg of a distant vertebrate forebear. [2] This is the stuff of science fiction novels. In fact Greg Bear has an excellent novel, Darwin's Radio that deals with the mysterious junk DNA in a speculative manner in a well written thriller. It won the Nebula Award and was nominated for a Hugo Award. In a nutshell:
Molecular biologist Kaye Lang, a specialist in retroviruses, believes that ancient diseases encoded in the DNA of humans can again come to life. But her theory soon becomes chilling reality. For Christopher Dicken -- a "virus hunter" at the Epidemic Intelligence Service -- has pursued an elusive flu-like disease that strikes down expectant mothers and their offspring. The shocking link: something that has slept in our genes for millions of years is waking up.
Looking on Bear's website, I see there is a sequel, Darwin's Children, due out soon. Cool! Bear is a great sci-fi writer.
This is an historic event: a great triumph for science, for the international community showing the world the virtues of cooperation, and a great day for humanity: a great leap forward, and a launching board for further discoveries. So much of what is to come lies in these now charted waters. The map is of course, not the territory. Much hard work remains to be done. And as with any technology, but maybe more so with this one, dealing as it does with the very stuff of life, there is great potential for abuse.
The genome can be viewed online at Human Genome Resources (degree in Genetic Science not included - your comprehension may vary). If you like pretty pictures, the United States Department of Energy's genomes.org website has graphics and links to other resources.
SOURCES:
[1] Final human genome sequence released, NewScientist.com
[2] Genes that count, NewScientist.com
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