PHYLOGENETIC-RELATIONSHIPS OF ENTOMOPATHOGENIC NEMATODES (HETERORHABDITIDAE AND STEINERNEMATIDAE) INFERRED FROM PARTIAL 18S RIBOSOMAL-RNA GENE-SEQUENCES
J. Liu et al., PHYLOGENETIC-RELATIONSHIPS OF ENTOMOPATHOGENIC NEMATODES (HETERORHABDITIDAE AND STEINERNEMATIDAE) INFERRED FROM PARTIAL 18S RIBOSOMAL-RNA GENE-SEQUENCES, Journal of invertebrate pathology, 69(3), 1997, pp. 246-252
Aligned 265-bp sequences of partial 18S rRNA gene were used to infer p
hylogenetic relationships among entomopathogenic nematodes by using ma
ximum parsimony and likelihood methods. Phylogenetic analyses support
Heterorhabditidae and Steinernematidae belonging to different monophyl
ies. There was more sequence divergence in Steinernema species than in
Heterorhabditis species. These results are congruent with the phyloge
nies based on morphological, life cycle, and distributional evidence.
Examination of all trees within 1% of the length of the most parsimoni
ous trees and bootstrap analyses support most relationships among Stei
nernema species but the relationships among Heterorhabditis species we
re not supported. We suggest that the partial 18S rRNA gene sequences
may be too conserved for phylogenetic inference among Heterorhabditis
species, but are well suited for phylogenetic inference within and amo
ng closely related families and genera of entomopathogenic nematodes a
nd for inferring phylogenetic relationships among Steinernema species.
(C) 1997 Academic Press.