![](https://borea.mnhn.fr/sites/default/files/styles/large/public/default_images/calendrier-2.jpg?itok=7fmmYsY4)
Le prochain séminaire BOREA/AVIV se tiendra le lundi 2 juillet 2018 de 16h à 17h30 dans l'amphithéâtre Rouelle (Bat de la Baleine), au Muséum national d'histoire naturelle (Paris).
Nous vous attendons nombreux pour l'intervention du Pr Dan Larhammar, Dept of Neuroscience, Uppsala University, Sweden
Titre : "The impact of genome doublings on vertebrate evolution - with special notes on lampreys"
The ancestor of the gnathostomes, i.e. the jawed vertebrates, underwent two tetraploidizations approximately 500 million years ago. These events are referred to as 1R and 2R for the first and second round of genome doubling. However, it has been exceedingly difficult to resolve whether the cyclostome lineage (the jawless lampreys and hagfish) branched off after 1R or after 2R. My lab has investigated numerous gene families, primarily endocrine and neuronal genes, and resolved their evolution. Several examples will be given: peptide hormones, neuropeptides and receptors, vision genes, ion channels,memory genes, etc. We are using several of these gene families trying to resolve the earliest vertebrate divergence event of gnathostomes and cyclostomes in relation to the tetraploidizations. Data will be presented for which the most parsimonious interpretation is that cyclostomes and gnathostomes share also the second tetraploidization, although the relationships have become obscured by chromosomal crossing-over events.
Invité par Sylvie Dufour UMR BOREA et Hervé Tostivint UMR ERE, Dpt Aviv