28 mars Susana Coelho, UMR8227 - Station Biologique CNRS UPMC
Origin and evolution of the sexes : new insights from the brown algae
Although the core mechanisms of sexual reproduction (meiosis and syngamy) are highly conserved across eukaryotes, the mechanisms that determine whether an individual is male or female are remarkably labile. In genetically controlled sexual systems, gender is determined by sex chromosomes, which have emerged independently and repeatedly during evolution. We are using the brown algae, a group that diverged from plants and animals more than a billion years ago, to gain insights into the evolution of haploid (UV) sex chromosomes. We investigated the conservation of sex-linked gene content among six brown algal species, belonging to two lineages, the kelps and the Ectocarpales, focusing on gene movement in/out of the U and V-specific regions. We analysed the consequences of sex linkage for the evolution of genes that have been residing in the sex-specific region in the different lineages at different evolutionary times. Our results highlight the dynamic nature of the U and V gene content across the different species compared with autosomes. We discuss how U and V gene content evolution may be related with the specific life history traits of each lineage, focusing on the level of sexual dimorphism, life cycle and sexual system.
4 avril : Pas de séminaire
11 avril : Pas de séminaire
18 avril : Charles Davis, Professor of Organismic and Evolutionary Biology, Curator of Vascular Plant Collection, Director, Harvard University Herbaria
The big, the bad, and the beautiful : parasitism and the origin of the world’s largest flowers
Parasitic plants are bizarre and have remained one of the last great challenges to resolve the flowering plant tree of life. The most charismatic of these species are Rafflesiaceae, which hold the distinction of producing the world’s largest flowers. I will discuss our efforts to clarify their evolutionary relationships. I will then draw on these findings to address their genetic and developmental origins from humbler beginnings. And finally, I will address how broad genomic studies in the group have elucidated the magnitude and directionality of host-to-parasite gene transfer in flowering plants.
13 juin Vyacheslav Yurchenko, Associate Professor and Lab Head,
Laboratory of Molecular Protozoology, University of Ostrava, Czech Republic
Trypanosomatids in the Next-Gen Sequencing era
12 septembre Roseli Pellens, ISYEB