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The double odyssey of Madagascan polystome flatworms leads to new insights on the origins of their amphibian hosts.

ABSTRACT: Polystomatid flatworms are parasites of high host specificity, which mainly infect amphibian hosts. Only one polystome species has so far been recorded from Madagascar despite the high species richness and endemicity of amphibians on this island. Out of the 86 screened Malagasy frog species, we recovered polystomes from 25 in the families Ptychadenidae and Mantellidae. Molecular phylogenetic analysis uncovered an unexpected diversity of polystome species belonging to two separate clades: one forming a lineage within the genus Metapolystoma, with one species in Ptychadena and several species in the mantellid host genera Aglyptodactylus and Boophis; and the second corresponding to an undescribed genus that was found in the species of the subfamily Mantellinae in the family Mantellidae. The phylogenetic position of the undescribed genus along with molecular dating suggests that it may have colonized Madagascar in the Late Mesozoic or Early Cainozoic. By contrast, the more recent origin of Metapolystoma in Madagascar at ca 14-2 Myr ago strongly suggests that the ancestors of Ptychadena mascareniensis colonized Madagascar naturally by overseas dispersal, carrying their Metapolystoma parasites. Our findings provide a striking example of how parasite data can supply novel insights into the biogeographic history of their hosts.

SUBMITTER: Verneau O

PROVIDER: S-EPMC2660977 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature

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The double odyssey of Madagascan polystome flatworms leads to new insights on the origins of their amphibian hosts.

Verneau Olivier O Du Preez Louis H LH Laurent Véronique V Raharivololoniaina Liliane L Glaw Frank F Vences Miguel M

Proceedings. Biological sciences 20090120 1662

Polystomatid flatworms are parasites of high host specificity, which mainly infect amphibian hosts. Only one polystome species has so far been recorded from Madagascar despite the high species richness and endemicity of amphibians on this island. Out of the 86 screened Malagasy frog species, we recovered polystomes from 25 in the families Ptychadenidae and Mantellidae. Molecular phylogenetic analysis uncovered an unexpected diversity of polystome species belonging to two separate clades: one for ...[more]

PMID: 19203917

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Project description:BackgroundThe current Brazilian population is the product of centuries of admixture between intercontinental founding groups. Although previous results have revealed a heterogeneous distribution of mitochondrial lineages in the Northeast region, the most targeted by foreign settlers during the sixteenth century, little is known about the paternal ancestry of this particular population. Considering historical records have documented a series of territorial invasions in the Northeast by various European populations, we aimed to characterize the male lineages found in Brazilian individuals in order to discover to what extent these migrations have influenced the present-day gene pool. Our approach consisted of employing four hierarchical multiplex assays for the investigation of 45 unique event polymorphisms in the non-recombining portion of the Y-chromosome of 280 unrelated men from several Northeast Brazilian states.ResultsPrimary multiplex results allowed the identification of six major haplogroups, four of which were screened for downstream SNPs and enabled the observation of 19 additional lineages. Results reveal a majority of Western European haplogroups, among which R1b-S116* was the most common (63.9%), corroborating historical records of colonizations by Iberian populations. Nonetheless, FST genetic distances show similarities between Northeast Brazil and several other European populations, indicating multiple origins of settlers. Regarding Native American ancestry, our findings confirm a strong sexual bias against such haplogroups, which represented only 2.5% of individuals, highly contrasting previous results for maternal lineages. Furthermore, we document the presence of several Middle Eastern and African haplogroups, supporting a complex historical formation of this population and highlighting its uniqueness among other Brazilian regions.ConclusionsWe performed a comprehensive analysis of the major Y-chromosome lineages that form the most dynamic migratory region from the Brazilian colonial period. This evidence suggests that the ongoing entry of European, Middle Eastern, and African males in the Brazilian Northeast, since at least 500 years, was significantly responsible for the present-day genetic architecture of this population.

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Dataset Information

The double odyssey of Madagascan polystome flatworms leads to new insights on the origins of their amphibian hosts.

Publications

The double odyssey of Madagascan polystome flatworms leads to new insights on the origins of their amphibian hosts.

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