title: Unravelling the riddle of Radix: DNA barcoding for species identification of freshwater snail intermediate hosts of zoonotic digeneans and estimating their inter-population evolutionary relationships.
abstract: Radix spp. are intermediate host snails for digenean parasites of medical and veterinary importance. Within this genus, species differentiation using shell and internal organ morphology can result in erroneous species identification, causing problems when trying to understand the population biology of Radix. In the present study, DNA barcoding, using cox1 and ITS2 sequences, identified populations of Radix auricularia and Radix balthica from specimens originally morphologically identified as Radix peregra from the UK. Assessment of cox1 and ITS2 as species identification markers showed that, although both markers differentiated species, cox1 possessed greater molecular diversity and higher phylogenetic resolution. Cox1 also proved useful for gaining insights into the evolutionary relationships of Radix species populations. Phylogenetic analysis and haplotype networks of cox1 indicated that R. auricularia appeared to have invaded the UK several times; some haplotypes forming a distinct UK specific clade, whilst others are more akin to those found on mainland Europe. This was in contrast to relationships between R. balthica populations, which had low molecular diversity and no distinct UK specific haplotypes, suggesting recent and multiple invasions from mainland Europe. Molecular techniques therefore appear to be crucial for distinguishing Radix spp., particularly using cox1. This barcoding marker also enables the population biology of Radix spp. to be explored, and is invaluable for monitoring the epidemiology of fluke diseases especially in the light of emerging diseases and food security.
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK. Electronic address: s.p.lawton@kingston.ac.uk.
authors.forename: Scott P
authors.initials: SP
authors.lastname: Lawton
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
authors.forename: Rivka M
authors.initials: RM
authors.lastname: Lim
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK.
authors.forename: Juliet P
authors.initials: JP
authors.lastname: Dukes
authors.affiliation: School of Life Sciences, Middlesex University, The Burroughs, London NW4 4BT, UK. Electronic address: s.kett@mdx.ac.uk.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Kett
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK. Electronic address: R.Cook@kingston.ac.uk.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Cook
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK. Electronic address: T.Walker@kingston.ac.uk.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Walker
authors.affiliation: Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT1 2EE, UK. Electronic address: R.Kirk@kingston.ac.uk.
authors.forename: Ruth S
authors.initials: RS
authors.lastname: Kirk
mesh_terms: D000818:Animals; D051545:Cyclooxygenase 1 / Q000032:analysis; D004247:DNA / Q000032:analysis; D058893:DNA Barcoding, Taxonomic / Q000379:methods*; D019143:Evolution, Molecular; D005618:Fresh Water / Q000469:parasitology*; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D058865:Introduced Species; D010802:Phylogeny; D058974:Phylogeography; D012908:Snails / Q000145:classification* / Q000235:genetics* / Q000469:parasitology; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary; D014481:United States; D015047:Zoonoses / Q000469:parasitology
chemical_list: D004247:DNA; D051545:Cyclooxygenase 1
keywords: DNA barcoding; Epidemiology; Intermediate hosts; Molecular diversity; Phylogenetics; Radix auricularia; Radix balthica; cox1