ITS2 variability of Biomphalaria (Mollusca, Planorbidae) species from the Paranapanema Valley (São Paulo State, Brazil): diversity patterns, population structure, and phylogenetic relationships

Abstract

The ribosomal DNA internal transcribed spacer 2 (ITS2) has been shown to be a useful genetic marker for species identification and phylogenetic reconstruction in the genus of freshwater snails Biomphalaria (Preston 1910). Additionally, ITS2 studies in Biomphalaria have uncovered significant intra-specific genetic variability suggesting the presence of cryptic species complexes. We obtained ITS2 sequences for the Biomphalaria species B. glabrata, B. tenagophila, B. occidentalis and B. peregrina from the Paranapanema Valley (São Paulo State, Brazil) and compared them with a comprehensive set of published Biomphalaria ITS2 sequences using Bayesian inference of phylogeny. Analysis of the resulting trees showed that the newly obtained B. glabrata sequences did not cluster with those from other Brazilian localities and that sub-structuring occurred among Brazilian B. tenagophila populations. Moreover, although ITS2 sequences seem to indicate clear genetic differentiation within both B. glabrata and B. tenagophila, evidence in support of the occurrence of cryptic species is more compelling for the latter. We discuss the significance and implications of the detected patterns of ITS2 variability for taxonomic studies in Biomphalaria.

Genetic diversity of the freshwater snail Biomphalaria tenagophila (d’Orbigny, 1835) (Gastropoda: Hygrophila: Planorbidae) across two coastal areas of southeast Brazil

“…The Bayesian analysis yielded trees with almost identical topologies in COI, 16S and ITS2 with phylogenetic relationships of some haplotypes well solved and some with weak support, especially haplotypes with sequences from the southern region. In general, the Bayesian analysis of the ITS2 sequences corroborates the finding of differentiated B. tenagophila sequences as previously observed in the middle Paranapanema (tuan & SantoS 2007).…”

“…There is evidence of partition of genetic variation in the genus Biomphalaria in different mitochondrial and nuclear haplotypes on a fine geographical scale, indicating that even geographically close populations are genetically differentiated (Mulvey & vRijenhoeK 1982, lanGand et al 1999, MaváReZ et al 2002, tuan & SantoS 2007, tuan et al 2012. The structuring of the genetic variability of Biomphalaria populations on a fine geographical scale may be a result of reproductive characteristics and physiological adaptations that allow the snails to survive droughts and floods through desiccation by reducing their metabolic activity (baRboZa et al 1985, vianey-liaud & lancaStRe 1986, tuan & SiMõeS 1989, baRboSa et al 2012, WeiR & Salice 2012.…”

“…In this study, PCR-amplified sequences from COI and 16SrDNA (16S) mitochondrial genes and the second internal transcribed spacer of nuclear ribosomal DNA (ITS2) were used to analyse the genetic variation in B. tenagophila. The mitochondrial genes were used because of their efficacy in inferring genetic patterns in populations associated with the effects of demographic variation within a species (aviSe et al 1984) and ITS2 because it had previously yielded robust phylogenetic signals in the characterisation of genetically differentiated lineages of B. tenagophila (tuan & SantoS 2007).…”

Distribuição e diversidade de espécies do gênero Biomphalaria em microrregiões localizadas no Médio Paranapanema, São Paulo, SP, Brasil

“…Neste caso, a fragmentação dos ecossistemas de água doce, manejados para atender as necessidades humanas, pode estar diretamente relacionada com a distribuição de espécies de Biomphalaria. Na primeira fase do estudo descrevemos a significativa diversidade genética, especialmente de Biomphalaria tenagophila, em criadouros adjacentes, localizados entre os Rios Paranapanema e Pardo, antigos focos de esquistossomose (Tuan & Santos 2007). Complementa tal estudo a analise de aspectos quantitativos da diversidade de Biomphalaria, para inferir sobre as variáveis que condicionam a permanência e a estabilidade de populações de caramujos em coleções d'água sujeitas a perturbações hidrológicas.…”

Molecular and morphological identification of Biomphalaria species from the state of São Paulo, Brazil

“… PCR - RFLP analysis of mitochondrial and nuclear genes ( Spatz et al 1999 ; Vidigal et al 1998 , 2000 ; Caldeira et al 2000 , 2009 ), fingerprinting techniques using nonspecific primers ( Abdel-Hamid et al 1999 ; Al-Quraishy et al 2014 ) and sequence analysis of COI and r16RNA genes and ITS-1 and ITS-2 sequences ( Woolhouse and Chandiwana 1989 ; Langand et al 1998 ; Vidigal et al 2000 ; Campbell et al 2000 ; DeJong et al 2003 ; Wethington et al 2007 ; Tuan and Santos 2007 ; Tuan et al 2012 ) have all produced results that allowed significant genetic differences in species and populations to be identified.…”