Roundworms, C. Elegans

Researchers are exploiting a recently discovered phenomenon known as RNA interference (RNAi) to inhibit the function of specific genes. This approach is technically simpler than the methods described above for disrupting genes. First observed in the roundworm C. elegans, RNAl refers to the ability of a double-stranded (ds) RNA to block expression of its corresponding single-stranded mRNA but not that of mRNAs with a different sequence. 

About one-third of the genes in humans, flies (Drosophila), and roundworms (C. elegans) are unique to each animal. 

The roundworm C. elegans has proven to be a valuable model organism for studies of cell birth, cell lineage, and cell death. What properties of C. elegans render it so well suited for these studies Why is so much information from C. elegans experiments of use to investigators interested In mammalian development ... 

First, the total number of protein-coding genes does not correlate in any simple way with standard conceptions about animal complexity (see Figure 9-34). Humans, for instance, have only about 1.75 times as many genes as the roundworm Caenorhabditis elegans. Likewise, C. elegans has about 1.4 times as many genes as the fruit fly Drosophila, which exhibits a much more complex body plan and more complex behavior. 

Other organisms applied in chemical genomics screens include the fruit fly Drosophila melanogaster), and Caenorhabditis elegans (C. elegans), which is a roundworm. 

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