The 5.8S rDNA sequences of 18 species of bursate nematodes (order Strongylida): comparison with rhabditid and tylenchid nematodes.

The 5.8S rDNA sequences of 18 species of bursate nematode were 153 bp in length and had a G + C content of 47-50%. Interspecific differences in rDNA sequence among the bursate nematodes were low (0-5.2%), but the extent of the sequence differences between the parasitic bursate nematodes, a free-living rhabditid nematode and 2 species of parasitic tylenchid nematodes (12-33%) suggests that the 5.8S rRNA gene may provide useful phylogenetic information with respect to the relationships of the different orders within the phylum Nematoda.