Poster

Abstract

Evolutionary inferences typically assume species-level monophyly, i.e., that 1) species represent genetically and reproductively independent lineages and 2) that reconstructed gene trees accurately reflect species trees. Polyphyly (as detected by gene/species conflicts) is common within marine taxa, however, suggesting that incomplete isolation and reticulate evolution often accompany marine lineage’s diversification. In this seminar I review selected case studies from brown algae radiations. Fucus and Pelvetiopsis (Fucaceae, Phaeophycea) are two sister genera of canopy-forming seaweeds with diversification centres in the N Atlantic and the NE Pacific, respectively. Both form multispecific intertidal assemblages where opportunities to hybridize are presumably high. Using phylogenetic and phylogeographic approaches I identify multiple instances of mtDNA introgression (Fucus) and of hybrid (polyploid) speciation (Pelvetiopsis). I show that organelle introgressions can be associated with climatic shifts, involve multiple species pairs and range geographically from local to complete organelle replacement of native alleles. Allopolyploidy may be linked with increased evolutionary success. I discuss the importance of an adequate genomic and geographical sampling to recognize regional introgression and hybrid speciation when reconstructing the evolutionary histories of hybridizing marine species.

Short CV

João Neiva graduated in Biology from the University of Évora (2004) and completed his PhD in Biological Sciences (Molecular Ecology) from the University of Algarve (2012). He is currently a post-doc member of the Biogeographical Ecology and Evolution (BEE) group at CCMAR, headed by Prof. Ester Serrão. João investigates evolutionary processes and phylogeographical patterns in the marine realm, using low-dispersal, canopy-forming brown algae with different thermal tolerances and geographical distributions as models. He integrates molecular (phylogenetic, phylogeographic, population genetic) and palaeo-environmental data to reconstruct past, present and future ranges of species and to investigate how demographic and genetic processes shape patterns of diversity at specific and infra-specific levels.  He is particularly interested in the roles of glacial-interglacial cycles and of hybridization in the evolution of recent marine radiations. Currently he integrates the project MARFOR: Functional Variability and Dynamics of Responses of Marine Forests to Global Change.

Atendance Certificate

MAY SEMINARS (programme download)