Thursday, January 30, 2003

Tree of Life
By MEREDITH GOAD, Portland Press Herald Writer
Copyright © 2003 Blethen Maine Newspapers Inc.

WEST BOOTHBAY HARBOR — There have been many big science projects in recent years, from the massive effort to decode the human genome to the launch of probes to Mars. But as big science projects go, the one that Charles O'Kelly is working on is a doozy.

O'Kelly, a senior research scientist at the Bigelow Laboratory for Ocean Sciences, is among a group of scientists across the country who are trying to reconstruct the "Tree of Life," the framework of animals, plants and microorganisms that illustrates the evolutionary history and diversity of life on Earth.

The $10 million "Assembling the Tree of Life" project will help to explain the relationships between the 1.75 million known species on the planet, revealing their similarities and differences. It may also have many practical uses, from the discovery of new medicines to the preservation of biodiversity.

The concept of a Tree of Life is "a big one that has been occupying intellectual thought for millennia," O'Kelly said. "It goes all the way back to Aristotle, who basically talked about the chain of being, the idea that there was some kind of a hierarchy in life."

The idea caught fire when Charles Darwin used tree imagery to describe the connectedness of life "with its everbranching and beautiful ramifications."

But never before have such advanced technological tools been available for actually assembling the tree.

Scientists involved with the project will use a combination of genetic data, computer modeling and morphology – information on the form and structure of a species – to figure out where the animals or plants they study fit into life's genealogy. They'll also be developing the molecular, morphological and computational tools that will be needed to push progress on the tree forward.

"We're trying to speed up how we put this together," said Diana Lipscomb, program director for the project at the National Science Foundation in Washington, D.C.

O'Kelly is part of a research group that is examining 50 of the green plants, from algae to flowers. The Bigelow researcher will be responsible for all of the work on green algae.

The green plant project is one of seven funded in October by the National Science Foundation, and includes scientists from Yale, Southern Illinois University, Utah State, the University of California-Berkeley, and the University of Washington. Collectively, they received just under $3 million.

The other six projects are studying spiders, bacterial DNA, fungi, parasitic roundworms, birds and dinosaurs.

The scientists who received the grants are expected to set up a framework for the branch of life they are working on that allows other researchers to work with it right away.

"Every part of the tree is going to become of interest to us, either intellectually or practically," O'Kelly said, "and the goal here is to make sure that we've got the tools so that when we have that interest we can go at it and we don't have to reinvent the wheel in order to do it. We can deal with it, and quickly."

The researchers are also supposed to set up systems to disseminate information about their branch of the tree so that it's readily available to students, teachers and anyone else who wants access to it, Lipscomb said.

Putting together those big branches will be no easy task. As many as 20,000 species of green algae alone have been identified, and whether or not it's a species often depends on "who's counting and how they're counting," O'Kelly said.

"We're in a situation where, if you have lions and tigers and bears, you know what a species is," he said. "If you have amoebae and flagellates and green algae, you don't know what a species is, and we are going to need to assemble data such as we're assembling here before we're going to be able to answer that question."

One form of algae that O'Kelly is working on right now, for example, sometimes puts out a little hair that helps it to take in nutrients. Algae that produce hairs were once thought to be fundamentally different from those that don't – and therefore in a different place on the tree of life.

"We're finding that's not important," O'Kelly said. "If it doesn't make hairs, it just doesn't make hairs. It can still be in the same group, still be on the same part of the tree of life."

That raises a big question: So what?

"Assembling the Tree of Life" is not just an expensive intellectual exercise. Information from the tree of life is used for all kinds of practical purposes, from "bioprospecting" for new drugs and agricultural products to tracking the origin and outcome of emerging diseases.

When it was discovered that yew trees in the Pacific Northwest contain substances powerful for combatting ovarian cancer, Lipscomb noted, scientists began looking at other types of yew trees to determine whether they produced the same kinds of chemicals.

"When (West Nile virus) first started showing up, killing birds and infecting people, people's first question was well, what is it?" Lipscomb said. "Where did it come from? And that required someone to go and look at it and figure out where it fit on this phylogenetic tree. Once they knew that, and they realized it came from the Old World, they knew exactly what they were dealing with and how to combat it."

O'Kelly said that even the algae he's working on could prove beneficial. They contribute to the productivity of the oceans and act as carbon sinks that can fight global warming. Each species interacts with others, and potentially useful chemicals are a part of those interactions.

Recently, O'Kelly and another Bigelow researcher published with some Japanese colleagues a paper on some new species of algae that produce omega-3 fatty acids, the substance found in fish oil that protects against heart disease.

"Here are organisms new to science," O'Kelly said, "and they make bodacious amounts of these omega-3 fatty acids, which of course have significance for human health."

Staff Writer Meredith Goad can be contacted at 791-6332 or at: mgoad@pressherald.com

Staff photo by Doug Jones

Charles O'Kelly, a senior research scientist at the Bigelow Laboratory for Ocean Sciences, returns culture samples of green algae to the shelves of a controlled environment room at the lab. His work is part of a $10 million project that will help to explain the relationships between Earth's 1.75 million known species.

Staff photo by Doug Jones

Charles O'Kelly focuses his microscope on a culture of green algae from a lagoon in the south of France while the image appears on the screen behind him and a computer program that will help him compare the sample with Pacific and Atlantic green algae in the Tree of Life Project.