DIDEOXY FINGERPRINTING - APPLICATION TO THE GENOTYPING OF ECHINOCOCCUS

Dideoxy fingerprinting is an efficient method for the detection of seq uence variation in PCR-amplified DNA segments. It is a hybrid between single-strand conformation polymorphism and dideoxy sequencing, employ ing only one dideoxynucleotide in the sequencing reaction. Herein, we report the application of dideoxy fingerprinting to genetically type c estodes of the genus Echinococcus, utilising the mitochondrial cytochr ome c oxidase subunit I as the gene sequence for analysis. All of the seven genotypes (G1, G4, G6, G8, O, V and M2) examined could be readil y differentiated from one another by their characteristic and reproduc ible dideoxy fingerprinting profiles. Only subtle variation in profile s was detected among some of the eight isolates representing genotype G1, and no variation was detected between two samples of genotype G4 a nd of genotype M2. The capacity of dideoxy fingerprinting to detect al l nucleotide variations over 150-250 bp fragments indicates that it sh ould be possible to distinguish among all of the genotypes of Echinoco ccus thus far described. Although employed herein to display sequence variation in the cytochrome c oxidase subunit I of Echinococcus, dideo xy fingerprinting could be used for the high-resolution analysis of nu cleotide variations in other parasite genes, without the need for DNA sequencing. This has important implications for studying the genetic s tructure of parasite populations. (C) 1998 Australian Society for Para sitology. Published by Elsevier Science Ltd. All rights reserved.