Thursday, June 28, 2001

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"Biologists at the University of California, San Diego have identified genes in the common fruit fly, Drosophila melanogaster, that appear to be counterparts of genes responsible for more than 700 different genetic diseases in humans."

""Scientists have long known that humans share many similar genes with fruit flies," says Ethan Bier, a professor of biology at UCSD who headed the research. "The surprise is how deep these similarities really are. Basically, every category of human genetic disease is well represented with a counterpart in the fly.""

redux [05.02.00]
The Scientist Confessions of an Ex-Fly Pusher
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"Perhaps the biggest puzzle of the fly genome is evident by considering the other two eukaryotes to have had their genomes laid bare--the yeast Saccharomyces cerevisiae and the nematode worm Caenorhabditis elegans.8 The million-celled fruit fly has 13,601 protein-encoding genes, compared to 18,425 for the 1,000-celled tiny worm and 6,000 or so for the unicellular yeast. "It's fascinating to think that there are only 13,601 genes, less than C. elegans and just a couple of times that of yeast. Thirteen thousand genes doesn't even sound like much to build a worm with, let alone a fly!" exclaims Michael Young, head of the laboratory of genetics at Rockefeller University, who studies clock genes.

Also surprising is that the fly seems to get along on very little. "Once we got the gene count, we realized that not many proteins are involved in this complicated little beast. The animal has a basic toolbox, and [it] can put bits and pieces of that box together to create a complex biological system that can execute a fantastic ability such as behavior," Young adds. The insect apparently employs nested genes and alternate splicing patterns that peel off different-size mRNAs from the same gene. The overall effect is to wring more than one meaning from a DNA sequence."

"And although a fly with a human head isn't a likely scenario, the human genome sequence will probably confirm and extend the homologies between us and them. More generally, the similar sizes and unexpected streamlined nature of the eukaryotic genomes sequenced to date is stimulating a great rethinking of how DNA orchestrates life. Concludes Smith, "There may only be a couple of thousand proteins in the living universe. But duplication and modification over and over has led to a plethora of genes that make up all the things that walk around our planet."

redux [10.26.00]
BioMedNet Advanced genomics promise fruit fly exposure
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"According to Gos Micklam, a bioinformatics expert who joined the group from industry last year, "Drosophila is a terrific model organism to work on." Despite its complexity, he notes, the fly has only twice as many genes as yeast. It is also backed by huge research interest worldwide that goes back a century or more, which has produced detailed phenotypic data.

In particular however, he draws a distinction between "deterministic" and "algorithmic" developmental mechanisms. For instance, he says, those mechanisms that create the nematode, Caenorhabditis elegans, are deterministic in that the fate of every cell is more or less pre-determined and specified from the start. But Drosophila's mechanisms are algorithmic, he notes; the cells do not have a fixed lineage, and their developmental fate is partly the result of communication between cells.

The task of integrating the huge amounts of data to produce a comprehensive profile of gene expression, which Micklam describes as "the real challenge of genomics," will take many years, he says."