Genes of Fruit Fly Unraveled
By: Daniel Q. Haney
Associated Press
February 19,2000
Scientists who hope to unravel the genetic blueprint of human beings say they have successfully tested out their
methods on a much smaller subject the fruit fly.
The achievement, revealed Friday, represents an important dry run of gene-sequencing methods that are aimed at
tracking down all 70,000 or so genes inside every human cell.
It is an important discovery in itself, however, since the fruit fly Drosophila melanogaster is a favorite of scientists
who study genetics. For almost 100 years, the bug has been the premier lab species for learning how the
appearance and traits of living things are hard-wired into their genes.
In the latest project, scientists decoded the fruit fly's genetic blueprint from end to end. They translated both the
actual genes and the less interesting bits of genetic filler that separate them along the chromosomes.
The project combined the expertise of Gerald Rubin's Drosophila Genome Project Group at the University of
California, Berkeley, with the powerful gene-sequencing machines and computers at Celera Genomics Corp., the
Rockville, Md., firm headed by J. Craig Venter.
Scientists from both groups announced the results at the annual meeting of the American Association for the
Advancement of Science.
They said they have unraveled more than 97 percent of the fly's genetic code and more than 99 percent of the
actual genes. In all, it turns out that every fruit fly cell contains 13,601 genes.
The scientists have lumped the fruit fly genes into broad categories, such as those that contain the code for enzymes
or for structural proteins. The duties of half of the genes are unknown, but the rest make proteins already familiar to
scientists.
Although about 1,600 tiny gaps remain, Rubin said they are filling these in at a rate of about 100 a day, and most of
these should be finished within a few months.
Rubin said three scientific papers on the work have been submitted for publication in the journal Science. Much of
the raw data are already available on the Internet at the National Library of Medicine's GenBank site.
To those who have spent their careers studying the fruit fly, the data are likely to offer many insights as well as
possibilities for new experiments. Among other things, Edward Lewis said it will mean scientists may spend as
much time scrutinizing newly available genetic code on computer screens as they now do in lab experiments.
''We have been looking forward to this for a long time. It really is a big deal,'' said Lewis, a veteran Drosophila
researcher at the California Institute of Technology.
One reason scientists study the genes of simple creatures like flies and worms is that similar genes often play
important roles in the internal workings of people.
Rubin said his team looked at 289 genetic flaws known to cause diseases in humans. Using the new data, they
looked for similar genes in the fruit fly and found that 60 percent of the human genes match up.
These include genes for such common human problems as kidney disease, Alzheimer's disease and cancer. In fact,
70 percent of the genes known to cause human malignancy were found to exist in similar form in the fruit fly.
Mark Adams, a scientist at Celera, said a longtime goal has been discovery of a fruit fly version of a human gene
called p53. This gene ordinarily corrects genetic errors, and defects in p53 are an extremely common contributor
to cancer.
Using the new data, scientists found the gene. ''It just jumped right out of the genome,'' Adams said.
Over the years, scientists have discovered many mutations that cause odd body shapes or unusual characteristics in
fruit flies. Recently, a gene dubbed Methuselah was discovered that makes fruit flies live about one-third longer
than usual. Adams said the new data show that the Methuselah gene is actually one of a large family and has 10
close relatives.
The Celera scientists used a method called whole genome shotgun sequencing. They decoded more than 3 million
fragments of the fly's genes, then looked for overlapping chunks so they could piece them together into a
continuous strand.
''This is a test case for us in anticipation of doing the human genome,'' said Celera's Eugene Myers.
