Intra- and interindividual variation in ITS1 of Paragonimus westermani (Trematoda: Digenea) and related species: implications for phylogenetic studies

van Herwerden, Lynne, Blair, David, and Agatsuma, Takeshi (1999) Intra- and interindividual variation in ITS1 of Paragonimus westermani (Trematoda: Digenea) and related species: implications for phylogenetic studies. Molecular Phylogenetics and Evolution, 12 (1). pp. 67-73.

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We investigated the utility of the ribosomal first internal transcribed spacer (ITS1) for phylogenetic studies on trematodes of the genus Paragonimus. Numerous clones containing ITS1 PCR products were sequenced for P. miyazakii, P. macrorchis, and members of the P. ohirai and P. westermani species complexes. Some additional data were obtained by direct sequencing of PCR products. The ITS1 is composed of three distinct regions: the short 5' end, followed by a tract of approximately 120 nucleotides which occurs a variable number of times in tandem, and the 3' region, which lacks repeats and is referred to as the "post-repeat" fragment. Sequences from all three regions can be aligned among the species studied. Our initial hypothesis, that the post-repeat region would be valuable for phylogenetic studies within the P. westermani complex, was proved wrong. Intraindividual sequence variation in P. westermani was sometimes greater than between individuals of the species complex. In the P. ohirai species complex, however, sequence variation within individuals was minimal. Possible reasons for these observations are discussed. We also wished to determine whether the length variants sequenced were the dominant variants present in Paragonimus species. This was done by probing Southern blots of genomic digests with an ITS1 fragment which lacks repeat sequences. There is generally greater abundance of large variants, with much lower abundance of small variants, such as those sequenced. Differences in ITS1 lengths are attributed largely to differing numbers of repeats, though some exceptions (which are discussed) were found.

Item ID: 28289
Item Type: Article (Research - C1)
ISSN: 1095-9513
Keywords: ribosomal DNA, repeats, ITS1, Paragonimus westermani, Paragonimus ohirai, size variants, concerted evolution
Date Deposited: 31 Jul 2013 23:34
FoR Codes: 06 BIOLOGICAL SCIENCES > 0604 Genetics > 060411 Population, Ecological and Evolutionary Genetics @ 50%
06 BIOLOGICAL SCIENCES > 0603 Evolutionary Biology > 060301 Animal Systematics and Taxonomy @ 50%
SEO Codes: 92 HEALTH > 9204 Public Health (excl. Specific Population Health) > 920404 Disease Distribution and Transmission (incl. Surveillance and Response) @ 50%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960805 Flora, Fauna and Biodiversity at Regional or Larger Scales @ 50%
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