01543nas a2200169   4500008004100000022001400041245004300055210003900098300000800137490000600145520110100151100001701252700001701269700002201286700001801308856004701326       2002                        eng d  a1471-214800aThe evolutionary position of nematodes0 aevolutionary position of nematodes  a1-70 v23 aBACKGROUND:The complete genomes of three animals have been sequenced by global research efforts: a nematode worm (Caenorhabditis elegans), an insect (Drosophila melanogaster), and a vertebrate (Homo sapiens). Remarkably, their relationships have yet to be clarified. The confusion concerns the enigmatic position of nematodes. Traditionally, nematodes have occupied a basal position, in part because they lack a true body cavity. However, the leading hypothesis now joins nematodes with arthropods in a molting clade, Ecdysozoa, based on data from several genes.RESULTS:We tested the Ecdysozoa hypothesis with analyses of more than 100 nuclear protein alignments, under conditions that would expose biases, and found that it was not supported. Instead, we found significant support for the traditional hypothesis, Coelomata. Our result is robust to different rates of sequence change among genes and lineages, different numbers of taxa, and different species of nematodes.CONCLUSION:We conclude that insects (arthropods) are genetically and evolutionarily closer to humans than to nematode worms.1 aBlair, Jaime1 aIkeo, Kazuho1 aGojobori, Takashi1 aHedges, Blair  uhttp://www.biomedcentral.com/1471-2148/2/7