Molecular phylogeographic studies on Paragonimus westermani in Asia

Abstract

The lung¯uke, Paragonimus westermani (Kerbert, 1878), is widely distributed in Asia, and exhibits much variation in its biological properties. Previous phylogenetic studies using DNA sequences have demonstrated that samples from north-east Asia form a tight group distinct from samples from south Asia (Philippines, Thailand, Malaysia). Among countries from the latter region, considerable molecular diversity was observed. This was investigated further using additional DNA sequences (partial mitochondrial cytochrome c oxidase subunit 1 (COI) and the second internal transcribed spacer of the nuclear ribosomal gene repeat (ITS2)) from additional samples of P. westermani. Phylogenies inferred from these again found three or four groups within P. westermani, depending on the method of analysis. Populations of P. westermani from northeast Asia use snail hosts of the family Pleuroceridae and differ in other biological properties from populations in south Asia (that use snail hosts of the family Thiaridae). It is considered that the populations we sampled can be divided into two species, one in north-east Asia and the other in south Asia.

Evidence of new species ofHaematoloechus(Platyhelminthes: Digenea) using partialcox1sequences

“…cox1 Sequences have been widely used to define species limits and phylogenetic affinities in the platyhelminthes (Bowles et al 1993(Bowles et al , 1995Bowles and McManus 1994;Iwagami et al 2000Iwagami et al , 2003Morgan et al 2003;Razo-Mendivil et al 2004; nevertheless, most of those studies used a region of the cox1 that overlaps only in a short fragment at the 5 0 end of the standard barcode. The generation of primers that amplify the standard barcode region for a wide variety of platyhelminth groups has been a challenge (Moszczynska et al 2009), and is still at the experimental stage.…”

“…The generation of primers that amplify the standard barcode region for a wide variety of platyhelminth groups has been a challenge (Moszczynska et al 2009), and is still at the experimental stage. Although the cox1 fragment traditionally used in platyhelminths is shorter than the standard barcodes, it has given valuable information about the taxonomy and phylogeny of different groups, most of the time supported by other genes and morphology (Iwagami et al 2000(Iwagami et al , 2003Morgan et al 2003;Razo-Mendivil et al 2004). This is apparently also true for Haematoloechus spp., since H. complexus, which was split in several clades in our analysis, was already proposed to be a complex of 'cryptic species' based on ribosomal DNA sequences (Leó n- Règagnon et al 1999;León-Règagnon 2003;Leó n-Règagnon and Brooks 2003).…”

A review on the molecular characterization of digenean parasites using molecular markers with special reference to ITS region

“…With the help of these studies, 3 new genera (Caulanus gen. nov., Latuterus gen. nov., (Miller & Cribb, 2007) and Allobilharzia gen. nov. (Kolářová et al, 2006) and 49 new species have been established. Molecular studies of ITS rDNA region verifi ed as promising genetic marker having broad range of application for phylogenetic analyses at generic and species level (Blair et al, 1999;Iwagami et al, 2000;Huang et al, 2004;Tandon et al, 2007;). According to Vilas et al (2005) and Al-Kandari et al (2011) ITS-1 is more variable than ITS-2 due to variable nucleotide repeats (Warberg et al, 2005 in microphallid species) and accretion of substitutions at higher rate (Morgan & Blair, 1995;van Herwerden et al, 1999;Tkach et al, 2000).…”

Phylogenetic relationship of ribosomal ITS2 and mitochondrial COI among diploid and triploid Paragonimus westermani isolates

“…Studies on phylogeny and/or intraspecific variation in Paragonimus species, using ITS2 and mtCOI sequences, have recently been reported Iwagami et al, 2000). Homogenization is most likely to occur if the ribosomal genes occur in a single tandem array on one chromosome, as seems to be the case in trematodes (Hirai et al, 1989).…”