Earthworm Genetics

12/10/1998

All Things Considered (NPR)

Linda Wertheimer, Noah Adams, Joe Palca

LINDA WERTHEIMER, HOST: Today, scientist announced that, for the first time, they had determined nearly the entire genetic sequence of a multicellular organism. In the past, researchers have only been able to determine the sequence of simple single-celled organisms like bacteria.

As NPR's Joe Palca reports, the latest achievement is expected to have an enormous impact on biology.

JOE PALCA, NPR REPORTER: The organism is a tiny round worm called caenorhabditis elegance, or C. elegans for short. It's less than 1/16 of an inch long and is made of a mere 959 cells. But it does have a simple nervous system, muscles of a sort, a digestive system, and a reproductive system.

And now 99 percent of the 97 million base pairs of DNA that make up its genome are known.  Half the sequence was determined by scientists in Cambridge, England, the other half by researchers at Washington University in St. Louis. Robert Waterston (PHD) led the U.S. sequencing team.

ROBERT WATERSTON, RESEARCHER, WASHINGTON UNIVERSITY, ST LOUIS: We have before us now all the pieces of puzzle that it takes to make a worm and it is indeed the challenge of the next decade or so to figure out how these pieces all work to put together a worm.

PALCA: While the worm sequence, which is published in the current issue of the Journal Science is of great biological significance, there are much broader implications of the C. elegans work than simply being able to assemble a worm.

According to Francis Collins, director of the Human Genome Project which helped pay for the worm sequencing work, it is a tenet of evolutionary biology that at least some of the genes in simple organisms will be similar to genes in more complex organisms. In fact, says Collins, more than 70 percent of the human disease genes that have been discovered so far have analogous genes in the worm.

FRANCIS COLLINS, DIRECTOR, HUMAN GENOME PROJECT: Certainly many investigators studying human biology have become worm biologists and more will be now with this particular instruction book in front of him because it allows him to answer questions that you couldn't do in the human perhaps not in a reasonable period of time, perhaps not at all.

PALCA: For example you could knock out a gene in the worm you think is involved in the growth of nerves and see what happens. You couldn't very well do that in a human.

Even before the complete sequence was worked out, human biologists have been making extensive use of research on C. elegans.

Robert Horvitz (PHD) of MIT says worm research has helped scientists understand a process called "programmed cell death," or apoptosis, where the number of cells in the body is carefully regulated.

ROBERT HORVITZ, MIT, BOSTON: If in a human this process of apoptosis is misregulated so that too many cells die or too few cells die, what happens is that disease results. The genetic pathway for apoptosis has been derived essentially in its entirety from studies of C. elegans. And this pathway has direct implications for a broad variety of human disorders, disorders that include cancers, retinal degenerations, stroke, heart attacks, auto-immune disease and a variety of infectious diseases including AIDS and more.

PALCA: Horvitz says this is just one example of what can be learned from C. elegans. Now with the entire sequence in hand, more scientists will more easily identify other human genes that have their counterparts in the worm.

Horvitz predicts the worm information will usher in a new era of drug discovery where pharmaceuticals companies can design and test new compounds based on what they learn from worm biology.

Francis Collins says the worm sequencing work also augers well for what is considered the holy grail in modern biology, the complete sequence of all three billion base pairs that make up the human genome.

COLLINS: The success of this enterprise predicts success for the human and that is not just an idle statement. Much of what has been learned from sequencing these 97 million base pairs of the round worm is already being adapted in a major way to the assault on getting the complete sequence of humans. It's no accident that the two laboratories that did this work on the roundworm are also the two laboratories with the largest effort on sequencing the human which we are in the very rapid growth phase in getting accomplished.

PALCA: Collins says the new target date for that project is 2003.

 
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