Assessing Nuclear and Mitochondrial DNA Sequence Variation Within Steinernema (Rhabditida: Steinernematidae)

Allen L. Szalanski, David B. Taylor, Peter G. Mullin


DNA sequence analysis was used to characterize the nuclear ribosomal DNA ITS1 region and a portion of the COII and 16S rDNA genes of the mitochondrial genome from Steinernema entomopathogenic nematodes. Nuclear ITS1 nucleotide divergence among seven Steinernema spp. ranged from 6 to 22%, and mtDNA divergence among five species ranged from 12 to 20%. No intraspecific variation was observed among three S. feltiae strains. Phylogenetic analysis of both nuclear and mitochondrial DNA sequences confirms the existing morphological relationships of several Steinernema species. Both the rDNA ITS1 and mtDNA sequences were useful for resolving relationships among Steinernema taxa.


dna sequencing; entomopathogenic nematodes; genetic variability; mitochondrial dna; nematode; ribosomal dna its; steinernema

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