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Resolving the evolutionary relationships of molluscs with phylogenomic tools
Stephen A Smith1, Nerida G Wilson, Freya E Goetz
1Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA.
Nature
|October 28, 2011
Summary
This study resolves mollusc evolutionary relationships using transcriptome data. Results support the Aculifera clade and Conchifera monophyly, clarifying the placement of Monoplacophora and Scaphopoda within Mollusca.
Area of Science:
- * Zoology
- * Evolutionary Biology
- * Phylogenomics
Background:
- * Mollusca exhibit vast morphological diversity, second only to Arthropoda in species richness.
- * Despite extensive study, the evolutionary relationships within Mollusca remain poorly resolved, impacting understanding of origins and morphological evolution.
- * Key unresolved questions include the phylogenetic position of shell-less aplacophorans and the monophyly of shelled molluscs (Conchifera).
Purpose of the Study:
- * To resolve the phylogenetic relationships among major molluscan groups using comprehensive molecular data.
- * To investigate the evolutionary history of shell loss and gain within Mollusca.
- * To provide a robust evolutionary framework for future studies on mollusc development and anatomy.
Main Methods:
- * Generation of transcriptome data for 15 diverse mollusc species.
- * Integration of new data with existing molecular datasets, resulting in analyses of up to 216,402 sites and 1,185 gene regions.
- * Application of multiple phylogenetic models and analytical methods to ensure robust results.
Main Results:
- * Strong support for the monophyly of Aculifera (molluscs with spicules, lacking true shells) and Conchifera (shelled molluscs).
- * Monoplacophora is resolved as the sister group to Cephalopoda, not other Conchifera.
- * A well-supported clade comprising Scaphopoda, Gastropoda, and Bivalvia is identified, with Scaphopoda and Gastropoda often as sister groups.
Conclusions:
- * The study provides a well-resolved phylogeny for Mollusca, clarifying long-standing evolutionary questions.
- * The findings support distinct evolutionary trajectories for shell-less and shelled molluscs.
- * The established phylogenetic framework will facilitate future research into mollusc evolution, development, and comparative anatomy.
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