Scientists Compare 12 Fruit Fly Genomes

An international research consortium of scientists, supported by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health (NIH), announced publications comparing the genome sequences of 12 closely related fruit fly species, 10 of which were sequenced for the first time.

The analyses identify thousands of novel genes and other functional elements in the insects' genomes, and describe how evolution has shaped the genomes of these important models for genetic research.

"This remarkable scientific achievement underscores the value of sequencing and comparing many closely related species, especially those with great potential to enhance our understanding of fundamental biological processes," said Francis S. Collins, M.D., Ph.D., director of NHGRI.

"Thanks to the consortium's hard work, scientists around the world now have a rich new source of genomic data that can be mined in many different ways and applied to other important model systems as well as humans."

The fruit fly is one of the most important model organisms in genetic research. In studies dating back nearly a century, researchers used fruit flies to discover the basic rules of inheritance and to study how a single cell, the fertilized egg, develops into a whole animal.

Although fruit flies have a genome that is 25 times smaller than the human genome, many of the flies' genes correspond to those in humans and control the same biological functions.

In recent years, fruit fly research has led to discoveries related to the influence of genes on diseases, animal development, population genetics, cell biology, neurobiology, behavior, physiology and evolution.

In papers published in the journal "Nature", the "Drosophila" Comparative Genome Sequencing and Analysis Consortium compare the genome sequences of "Drosophila melanogaster", which was published in 2000, and "D. pseudoobscura", published in 2005, with the recently sequenced genomes of "D. sechellia", "D. simulans", "D. yakuba", "D. erecta", "D. ananassae", "D. persimilis", "D. willistoni", "D. mojavensis", "D. virilis" and "D. grimshawi".

In addition, two companion manuscripts in "Nature" were contributed by researchers from the Laboratory of Cellular and Developmental Biology of the National Institute of Diabetes and Digestive and Kidney Diseases, at NIH.

The work was carried out by hundreds of scientists from more than 100 institutions in 16 countries. The sequencing of the 10 new genomes was led by Agencourt Bioscience Corp., Beverly, Mass.

Other sequencing centers contributing to the sequencing were Washington University School of Medicine, St. Louis, Mo., the Broad Institute of MIT and Harvard, Cambridge, Mass., and the J. Craig Venter Institute, Rockville, Md. The sequencing centers were funded as part of NHGRI's Large-Scale Sequencing Research Network.

To the average person, one fruit fly hovering around an overripe banana looks pretty much like any other. Researchers found that, at first glance, the genomes of the various types of fruit flies appear quite similar. However, a more detailed examination reveals that only 77 percent of the approximately 13,700 protein-coding genes in "D. melanogaster" are shared with all of the other 11 species.

Scientists observed that different regions of the fruit fly genomes, including protein-coding genes and gene families, are evolving at different rates. For example, genes involved in taste and smell, detoxification and metabolism, sex and reproduction, and immunity and defense appear to be the most rapidly evolving in the fruit fly genomes.

A project leader and co-author for the studies, William M. Gelbart, Ph.D., of Harvard University in Cambridge, Mass., said "The availability of the 12 fruit fly genomes resulted in a dramatic increase in resolution allowing us to examine how evolution has fine-tuned biological processes. Our work shows that discovery power increases with the number of genomes available for comparison."