THE NEMATODE CAENORHABDITIS-ELEGANS AND ITS GENOME

Over the past two decades, the small soil nematode Caenorhabditis eleg ans has become established as a major model system for the study of a great variety of problems in biology and medicine. One of its most sig nificant advantages is its simplicity, both in anatomy and in genomic organization. The entire haploid genetic content amounts to 100 millio n base pairs of DNA, about 1/30 the size of the human value. As a resu lt, C. elegans has also provided a pilot system for the construction o f physical maps of larger animal and plant genomes, and subsequently f or the complete sequencing of those genomes. By mid-1995, approximatel y one-fifth of the complete DNA sequence of this animal had been deter mined. Caenorhabditis elegans provides a test bed not only for the dev elopment and application of mapping and sequencing technologies, but a lso for the interpretation and use of complete sequence information. T his article reviews the progress so far toward a realizable goal--the total description of the genome of a simple animal.