Browsing by Author "Avia, Komlan"
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- Development of tools to rapidly identify cryptic species and characterize their genetic diversity in different European kelp speciesPublication . Mauger, Stéphane; Fouqueau, Louise; Avia, Komlan; Reynes, Lauric; Serrao, Ester; Neiva, J.; Valero, MyriamMarine ecosystems formed by kelp forests are severely threatened by global change and local coastline disturbances in many regions. In order to take appropriate conservation, mitigation, and restoration actions, it is crucial to identify the most diverse populations which could serve as a “reservoir” of genetic diversity. This requires the development of specifc tools, such as microsatellite markers to investigate the level and spatial distribution of genetic diversity. Here, we tested new polymorphic microsatellite loci from the genome of the kelp, Laminaria digitata, and tested them for cross-amplifcation and polymorphism in four closely related congeneric species (Laminaria hyperborea, Laminaria ochroleuca, Laminaria rodriguezii, and Laminaria pallida). Adding these 20 new microsatellite loci to the ten L. digitata loci previously developed by Billot et al. (Mol Ecol 7:1778-1780, 1998) and Brenan et al. (J R Soc Interface 11:1-12, 2014) and to the ten L. ochroleuca loci previ ously developed by Coelho et al. (Conserv Genet Resource 6:949-950, 2014), we retained a total of 30 polymorphic loci for L. digitata, 21 for L. hyperborea, 16 for L ochroleuca, 18 for L. rodriguezii, and 12 for L. pallida. These markers have been tested for the frst time in the last two species. As predicted, the proportion of markers that cross-amplifed between species decreased with increasing genetic distance. In addition, as problems of species identifcation were reported in this family, mainly between L. digitata and Hedophyllum nigripes, but also between L. digitata, L. hyperborea, and L. ochroleuca in areas where their range distributions overlap, we report a rapid PCR identifcation method based on species-specifc COI mitochondrial primers that allows these four species of kelp to be rapidly distinguished.
- Origin and evolutionary trajectories of brown algal sex chromosomes.Publication . Barrera-Redondo, Josué; Lipinska, Agnieszka P.; Liu, Pengfei; Dinatale, Erica; Cossard, Guillaume; Bogaert, Kenny; Hoshino, Masakazu; Craig, Rory J.; Avia, Komlan; Leiria, Goncalo; Avdievich, Elena; Liesner, Daniel; Luthringer, Rémy; Godfroy, Olivier; Heesch, Svenja; Nehr, Zofia; Brillet-Guéguen, Loraine; Peters, Akira F.; Hoarau, Galice; Pearson, Gareth Anthony; Aury, Jean-Marc; Wincker, Patrick; Denoeud, France; Cock, J Mark; Haas, Fabian B.; Coelho, Susana M.Research on the biology and evolution of sex chromosomes has primarily focused on diploid XX/XY and ZW/ZZ systems. In contrast, the rise, evolution and demise of U/V systems has remained an enigma. Here we analyse genomes of nine brown algal species with different sexual systems to determine the history of their sex determination. U/V sex chromosomes emerged between 450 and 224 million years ago, when a region containing the pivotal male-determinant MIN ceased recombining. Seven ancestral genes within the sex-determining region show remarkable conservation over this vast evolutionary time, although nested inversions caused expansions of the sex locus, independently in each lineage. We evaluate whether these expansions are associated with increased morphological complexity and sexual differentiation, and show that taxonomically restricted genes evolve unexpectedly often in U and V chromosomes. We also investigate two situations in which U/V-linked regions have changed. First, we demonstrate that convergent evolution of two monoicous species occurred by ancestral males acquiring U-specific genes. Second, the Fucus dioecious system involves new sex-determining gene(s), acting upstream of formerly V-specific genes during development. Both situations have led to the demise of U and V chromosomes and erosion of their specific genomic characteristics.