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The rDNA Internal Transcribed Spacer Region as a Taxonomic Marker for Nematodes

Thomas O. Powers, University of Nebraska-Lincoln
T. C. Todd, Kansas State University
A. M. Burnell, St. Patrick's College, Maynooth (Pontificial University)
P. C. B. Murray, St. Patrick's College, Maynooth (Pontificial University)
C. C. Flemming, Department of Agriculture of Northern Ireland
Allen L. Szalanski, Nebraska Game and Parks Commission
B. A. Adams, University of Nebraska-Lincoln
T. S. Harris, University of Nebraska-Lincoln

Document Type Article

Published in Journal of Nematology (I997) 29(4):441-450; © The Society of Nematologists 1997; Used by Permission


The ITS region from a wide taxonomic range of nematodes, including secernentean and adenophorean taxa, and free-living, entomopathogenic, and plant-parasitic species, was evaluated as a taxonomic marker. Size of the amplified product aided in the initial determination of group membership, and also suggested groups that may require taxonomic reevaluation. Congeneric species often displayed identically sized ITS regions, but genera such as Pratylenchus and Tylenchorhynchus had species with large differences in size. ITS heterogeneity in individuals and populations was identified in several nematode taxa. PCR-RFLP of ITS1 is advocated as a method of taxonomic analysis in genera such as Helicotylenchus that contain numerous species with few diagnostic morphological characteristics.