Doubling the Rewards: Testis ESTs for Drosophila Gene Discovery and Spermatogenesis Expression Profile Analysis
- University of Washington, Seattle, Washington 98195, USA
This extract was created in the absence of an abstract.
One of the rewards of completing, or essentially completing, the genomic sequence of reference organisms is to get an idea of the number of genes it takes to build an organism. The current consensus is that 6142 protein-encoding genes keep the budding yeast Saccharomyces cerevisiae alive and well, while the worm Caenorhabditis elegans has on the order of 19,099 genes. It was somewhat gratifying for Drosophilists to learn this year that the fly might be able to make do in life with fewer genes than the worm does; Adams et al. (2000) predicted 13,601 genes from the sequence of the 120-Mb euchromatic portion of theDrosophila melanogaster genome. The remaining 60 Mb of the fly genome is heterochromatic, and most of it is unclonable. Of the proportion of heterochromatin that is cloned, only small bits have been sequenced, and these fragments cannot be easily aligned because of interruptions by repetitive sequences. However, genetic studies predict that heterochromatin will contribute at least several dozen genes, and perhaps substantially more, to the total gene count (Gatti and Pimpinelli 1992). Hence, the estimate of 13,601 is a conservative one for the gene number in D. melanogaster, but just how conservative it may be is an open question. How many more hundreds or thousands of genes remain to be discovered for Drosophila? How can we best go about the business of finding these genes and deciphering their functions?
Yeast researchers have set the gold standard for addressing such questions in functional genomics, because they can delete each of the predicted open reading frames in the yeast genome and examine consequences in vivo (Winzeler et al. 1999). Unfortunately, such approaches …
