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• 5 years programme (2017-2021)
• Coordinator: Marie-Laure Guillemin (Universidad austral de Chile, ~165k€). For Igepp, Solenn Stoeckel (~3k€).
• Contact: solenn.stoeckel@inrae.fr

Evolutionary genomics of Gracilaria chilensis, a partially clonal cultivated alga in Chile

G. chilensis is a species of Gracilariaceae that plays a highly relevant place in the agar market world wide. It is one of the few species of algae that has been truly domesticated (Valero et al. In revision) and is indeed the only species of seaweed cultivated at an industrial level in Chile (Buschmann et al. 2008). Demographic, eco-physiological and genetic studies have demonstrated that the species have passed through multiple expansion and transoceanic colonization events within the Pacific. Also, recurrent bottlenecks could have affected the populations in Chile and domestication and cultivation have modified in depth the selective pressure exerted on cultivated individuals, the life history traits and the demographic and genetic structure of farmed populations (Guillemin et al. 2008 and 2014b and references therein). This species represents a very interesting model to reconstruct a complex evolutionary scenario of successive bottlenecks due to a primary introduction followed by exploitation, domestication and cultivation. In addition, contrasting patterns of genetic diversity across the whole genome between farms and natural populations may allow to identify, for the first time in a seaweed, the genomic signature of domestication.

We aim in this project deciphering the complex evolutionary history of G. chilensis using population genomic tools and a comprehensive sampling including populations from the whole distribution range of the species and individuals living in contrasting habitats (rocky substrates, soft substrates that have not been highly influenced by human activities and farms planted in soft substrate).

Demecology will be implied in this project to develop mechanistic population genetics model to test for successive bottlenecks, genomic signature of adaptation and human selection in partially clonal populations and will participate to analyze the genotypic diversity, level of heterozygosity and reproductive mode between fixed and floating populations.