Genome of Fruit Fly Sequenced

March 24, 2000; Westport (Reuters Health) -- An international team of scientists has released the "substantially complete" genome sequence of Drosophila melanogaster , the model organism for genetic and developmental research. "The annotated genome sequence of Drosophila melanogaster , together with its associated biology, will provide the foundation for a new era of sophisticated functional studies," Dr. Mark D. Adams, of Celera Genomics, in Rockville, Maryland, and colleagues say in the March 24th issue of Science . In the journal, the scientists describe for the first time the full genome sequence of D. melanogaster, which was obtained using a whole-genome "shotgun" sequencing strategy.

Approximately one-third of the 180-megabase genome is centric heterochromatin , consisting mainly of short, simple sequence repeats. The 120 MegaBase euchromatin segment is found on two large autosomes and the X chromosome and 1 MegaBase is on a small fourth chromosome, according to the researchers. The Drosophila genome contains approximately 13,600 genes that encode a diverse group of molecules, including transcription and translation factors, cytochrome P450 mono-oxygenases, solute transporters, and metabolic factors. Moreover, the scientists found that the Drosophila genome contained many genes that were homologues for disease-associated genes in humans, Dr. Adams told Reuters Health. "Many of those weren't previously known to exist in Drosophila." This finding suggests that Drosophila may be a more useful tool than expected for studying the cellular and molecular processes underlying human disease.

"The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans," Dr. Adams and colleagues write in the journal. "Even though the human genome is much more complex, the fruit fly is a lot more like humans than many of us may want to acknowledge," co-author, Dr. Steve Scherer, of Baylor University, notes elsewhere. "We share many of the same genes and biochemical pathways." Dr. Adams elaborated to Reuters Health that "something that we learn in Drosophila is a good candidate for that information being applicable in humans."

The reported genome sequence contains a few "gaps" that the scientists are working to close. Once this work is finished, "the diversity of predicted genes and gene products will serve as the raw material for continued experimental work aimed at unraveling the molecular mechanisms underlying development, behavior, aging, and many other processes," they conclude.

In a related Science report, Drs. Thomas B. Kornberg and Mark A. Krasnow, of the University of California at San Francisco and Stanford University, respectively, remark that the new Drosophila sequence may have yet another important use, as "the Rosetta Stone for deciphering the human genome."

Science (2000); Vol. 287, pp. 2185-2195 and pp. 2218-2220.