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Past Projects

Evolution of Shell Loss in Opisthobranch Gastropods

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A fundamental question in comparative biology is whether similar morphological structures are homologous or non-homologous, i.e., homoplastic. Because technological advances now permit it, one aspect of this question that has recently emerged is to elucidate the developmental processes involved in the formation of homologous anatomical features. Are homologous morphological features generated by homologous developmental processes? Can homoplastic features be governed by processes that are homologous at the molecular level? Sea slugs (Mollusca, Gastropoda, Opisthobranchia) are an ideal model system to address these questions because of rampant morphological homoplasy (i.e. convergences, reversals and parallelisms). Recent development of more reliable phylogenies and a growing pool of genomic data can now allow us to get at the mechanistic aspects of morphological homoplasy. In brief, the goal of this project will be to use a group of sea slugs, the sea hares (Opisthobranchia, Anaspidea), to develop a new model system to study developmental homoplasy through an integrative approach.

 

Metazoan Evolution and Mitochondrial Genomics

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Mitochondrial genomes are still underrepresented in phylogenetic studies relative to single gene phylogenies, and nowadays metazoan phylogeny is a subject of major research focus since multiple disciplines rely heavily on the presently accepted trees. The current dogma accepts that bilaterian animals diverged from the paraphyletic diploblasts at least 550 mya during the Cambrian radiation and that Bilateria is made up by protostomes and deuterostomes. The greatest number of animal phyla are now known to be of protostome origin. Molecular phylogenies have, however, split this assemblage into two new clades, the Lophotrochozoa and the still controversional Ecdysozoa. Apart from this level of agreement, many of the relationships among invertebrate phyla are still contentious. We are using mitochondrial genomes to help resolve/postulate new hypotheses for the phylogenetic placement of several unresolved relationships within Lophotrochozoa, the monophyly of several phyla and lower level relationships within diverse groups such as anthozoan cnidarians and opisthobranch gastropods.