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Mutation scanning for sequence variation in three mitochondrial DNA regions for members of the Contracaecum osculatum (Nematoda: Ascaridoidea) complex
Author(s) -
Hu Min,
D'Amelio Stefano,
Zhu Xingquan,
Paggi Lia,
Gasser Robin
Publication year - 2001
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/1522-2683()22:6<1069::aid-elps1069>3.0.co;2-t
Subject(s) - biology , mitochondrial dna , genetics , single strand conformation polymorphism , polymerase chain reaction , nucleic acid sequence , ribosomal rna , dna , microbiology and biotechnology , gene
Anisakid nematodes of seals from different geographical origins, previously identified by multilocus enzyme electrophoresis as Contracaecum osculatum A (CoA), C. osculatum B (CoB), C. osculatum C (CoC), C. osculatum D (CoD), C. osculatum E (CoE) and C. osculatum baicalensis (Cob), were characterised genetically using a mutation scanning approach, in order to define genetic markers for their specific identification and differentiation. Three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit I (COI), and the small and large subunits of rRNA (ssrRNA and lsrRNA, respectively) were amplified separately from individual nematodes by polymerase chain reaction (PCR), analysed by single‐strand conformation polymorphism (SSCP), and samples displaying sequence variability were subjected to sequencing. Forty‐six haplotypes were defined for 62—66 individuals (representing the six members of C. osculatum ). All taxa except CoD and CoE could be identified, or delineated from one another, by nucleotide differences in the COI, ssrRNA and/or lsrRNA sequences. For all three mtDNA regions, 4 (10.5%), 7 (18.4%), 15 (39.5%) and 11 (28.9%) of 38 nucleotide positions were considered diagnostic (fixed) and could thus unequivocally delineate CoA, CoB, CoC and Cob. The lack of an unequivocal nucleotide difference in any of the three mtDNA sequences between CoD and CoE was in accordance with previous ribosomal DNA sequence data but inconsistent with multilocus enzyme electrophoretic data. Using all fixed nucleotide positions, CoA, CoD/E and CoB were genetically more similar to Cob than each was to CoC, similar to previous findings. In spite of not being able to distinguish among all six taxa of C. osculatum , the present study demonstrated clearly the usefulness and attributes of the mutation scanning approach for investigating population genetic structures of species of parasitic nematodes.