Molecular evidence supports an African affinity of the Neotropical freshwater gastropod,Biomphalaria glabrata, Say 1818, an intermediate host forSchistosoma mansoni

Abstract

Freshwater snails of the genus Biomphalaria, Preston 1910, are the most important and widely distributed intermediate hosts of Schistosoma mansoni, the blood fluke responsible for human intestinal schistosomiasis, in Africa and the Neotropics. S. mansoni is thought to have been imported repeatedly into the Americas during the last 500 years with the African slave trade. Surprisingly considering that the New and Old World separated 95-106 million years (Myr) ago, the disease rapidly became established due to the presence of endemic susceptible hosts. Reconstructing the phylogenetic relationships within Biomphalaria may provide insights into the successful intercontinental spread of S. mansoni. Parsimony and distance analyses of mitochondrial and nuclear sequences show African taxa to be monophyletic and Neotropical species paraphyletic, with Biomphalaria glabrata forming a separate clade from other Neotropical Biomphalaria, and ancestral to the African taxa. A west to east trans-Atlantic dispersal of a B. glabrata-like taxon, possibly as recently as the Plio-Pleistocene (1.8-3.6 Myr ago) according to a general mitochondrial clock, would fit these observations. Vicariance or an African origin for B. glabrata followed by multiple introductions to South America over the past 500 years with the African slave trade seem unlikely explanations. Knowledge of the phylogenetic relationships among important intermediate host species may prove useful in furthering control measures which exploit genetic differences in susceptibility to parasites, and in elucidating the evolution of schistosome resistance.

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

“…Species of planorbid snails belonging to the genus Biomphalaria, which includes the vectors of the blood fluke Schistosoma mansoni, have recently received increasingly attention in molecular systematic and phylogeography studies (Campbell et al, 2000;Vidigal et al, 2000Vidigal et al, , 2004DeJong et al, 2001;Mavárez et al, 2002;Pointier et al, 2005). These studies have largely supported the pivotal body of work on the taxonomy of Neotropical Biomphalaria carried out by malacologist Lobato Paraense (Paraense, 2001) and, additionally, uncovered interesting patterns of intraspecific variability (Mavárez et al, 2002;Vidigal et al, 2004).…”

“…Among the genetic markers used so far in studies on Biomphalaria, the nuclear ribosomal DNA (rDNA) internal transcribed spacers (ITS) have been shown to be particularly useful for species identification and phylogenetic reconstruction (Campbell et al, 2000;Vidigal et al, 2000;Pointier et al, 2005). Furthermore, ITS sequence studies have revealed and/or confirmed sub-structuring within widely distributed species such as B. glabrata and B. tenagophila (Mavárez et al, 2002;Vidigal et al, 2004), adding to the body of evidence indicating that these nominal taxa may constitute complexes of cryptic species (Woodruff and Mulvey, 1997;Spatz et al, 1999).…”

Detection of Genetic Relationship in the Tree of Life of Some Quail Through Molecular Markers Analyses

“…Cytochrome oxidase I (COI) is a mitocondrial (mt) gene with an evolution rate smaller than that observed for mtDNA and its amino acid sequence is highly conserved across phyla. Molecular tools, using mtDNA COI region, have been used in several genetic studies 5,6,7,8,9 . The SEMA3E gene encodes a secreted class 3 semaphorin that triggers repulsion of endothelial cells in specific vascular beds and modulates axonal growth and synaptic connectivity for the correct wiring of the CNS 10 will be used in this work.…”

Biomphalaria spp. (Preston, 1910) snails in the municipality of Juiz de Fora, Zona da Mata Mineira mesoregion, ate of Minas Gerais, Brazil

“…Biogeographic studies indicate that an ancestor of B. glabrata from the New World dispersed in the Pliocene-Pleistocene (Campbell et al 2000, DeJong et al 2001, probably by rafting on vegetation or by eggs carried by migratory birds, crossing the Atlantic to Africa and giving rise to the current African species (Lockyer et al 2004).…”