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University of Iowa News Release

Sept. 28, 2004

Photos: Debashish Bhattacharya (top) and John Logsdon

UI Biologists Receive $1.6 Million NSF Tree Of Life Grant

Two University of Iowa researchers have received a grant to pursue an unrealized dream of famed 19th century naturalist Charles Darwin -- to unravel the genealogy of all living things.

Debashish Bhattacharya, principal investigator and associate professor, and John Logsdon, co-principal investigator and assistant professor, in the UI College of Liberal Arts and Sciences Department of Biological Sciences and the Roy J. Carver Center for Comparative Genomics, have received a five-year, $1.6 million National Science Foundation (NSF) grant to help scientists construct a family tree for all life on Earth.

The collaborative project is part of a larger NSF-funded effort formally called "Assembling the Tree of Life." The UI researchers' role in the project will be to uncover relationships among eukaryotes -- plant and animal cells having nuclei -- by analyzing the DNA sequences of nine genes from 200 species of predominantly free-living protists, or one-celled organisms. Protists, mostly plants such as algae, comprise the bulk of all life. Bhattacharya says that analyses of the resulting data will combine existing phylogenetic, or tree-building, approaches with those developed for the project.

"To truly understand biological diversity on Earth requires that microorganisms be correctly placed on the tree of life," Bhattacharya says.

He explains that life on Earth can be classified as falling into one of two forms: prokaryotes consisting of bacteria and archaea, all of which are microbial, and eukaryotes -- cells with nuclei, including plants, animals, and fungi. The microbial eukaryotes, or protists, he will study are characterized by tremendous cellular diversity and play an essential role in ecosystems, such as carbon fixation in marine systems, and as causative agents of malaria and other infectious diseases.

Bhattacharya and Logsdon plan to work with at least two postdoctoral fellows and four graduate students, as well as train undergraduates in all aspects of the research. The project also includes the development of a workshop on collection and identification (by light microscopy) of protists. Finally, micro*scope, a web-based tool for exploring eukaryotic diversity (http://www.mbl.edu/microscope) will be expanded to include educational materials at multiple levels.

In a 2002 paper published in the journal Proceedings of the National Academy of Sciences (PNAS), Bhattacharya revised scientists' estimate of the date of origin of photosynthetic algae -- responsible for about one-half of Earth's oxygen and the primary producers in the food chain -- from some 500 million years ago to 1.2 billion years ago. The paper offered evidence for the single origin of a vast assemblage of photosynthetic algae, such as diatoms and giant kelps that contain the light-harvesting pigment chlorophyll c, and changed views on when the Earth was first dominated by photosynthetic eukaryotes.

Bhattacharya directs one of the best-equipped laboratories of its kind for investigating the evolutionary history of algae. His group previously received a $790,000 grant from the NSF and the U.S. Department of Agriculture and a $450,000 grant from NASA for unraveling the evolution of algal genomes.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

CONTACTS: Gary Galluzzo, 319-384-0009, gary-galluzzo@uiowa.edu.