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Gretchen Cook-Anderson
Headquarters, Washington
(Phone: 202/358-0836)

Sept. 9, 2004
Molecular Biologists Uproot Perspective of Ancient Ancestry
A study funded in part by NASA has uprooted the "Tree of Life" metaphor that describes how all organisms are related.

The new perspective, reported in today's issue of the journal Nature, has produced significant implications for eukaryotes (cells with nuclei). The group includes all multi-cellular forms of life, including humans, animals and plants.

"It's not a tree; it's actually a ring of life," said Dr. James A. Lake, professor of molecular biology, University of California at Los Angeles (UCLA). "A ring explains the data far better."

The "Tree of Life," with its evolutionary branches and roots showing groups of bacteria on the bottom and multi-cellular animals on the higher branches, therefore is a misnomer according to Lake.

"Through the use of genomics, we show the fusion of two microbial groups created the first eukaryote," Lake said. "There have been theories, but we have never known where eukaryotes came from before. Eukaryotes inherited two sets of genomes from very different microbial groups that do not have a cellular nucleus, called prokaryotes," he said.

NASA, the National Science Foundation, Department of Energy, and the National Institutes of Health funded the research, based on an analysis of more than 30 genomes.

Lake conducted the research with Maria Rivera, a research scientist in UCLA's department of molecular, cell, and developmental biology, and the university's astrobiology program.

For information about astrobiology at NASA on the Internet, visit:


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