Molecular analysis of nematode diversity and the evolution of parasitism

A through and coherent classification of the phylum Nematoda is essential i f the evolution of countless phenotypes is to be understood. Here, Mark Dor ris, Paul De Ley and Mark Blaxter discuss how the application of molecular phylogenetics is helping to resolve some of the inconsistencies in morpholo gical classification and phylogeny by establishing relationships between fr ee-living and parasitic groups, showing possible patterns underlying the or igins of parasitism and placing key nematode species in an evolutionary con text for comparative study.