Hybridizations between Musa species and subspecies, native to the Southeast Asia/New Guinea region, are at the origin of diploid and triploid cultivated bananas. Our objectives are to better understand these hybridization processes and to identify all ancestral contributors to the genomes of cultivated bananas.

To this end, we have implemented bioinformatics tools that use SNP information from sequencing data to characterize the mosaics formed by the different ancestral origins along banana chromosomes (GenomeHarvest project, Agropolis Fondation).

Characterization of A (Musa acuminata) and B (Musa balbisiana) genome composition along the chromosomes of diploid and triploid A/B hybrids revealed recombination events between A and B chromosomes and characterized the interspecific mosaic structure of these genomes (Baurens et al., 2019).

Characterization of the contributions of Musa acuminata subspecies using a dataset of 24 accessions revealed relatively complex genome mosaics suggesting more meiosis steps than anticipated; it also identified the existence of as yet unknown ancestors (Martin et al., 2020).

We are analyzing high-coverage Illumina sequencing data from a larger sampling of wild and cultivated diversity (collaboration with GENOSCOPE, France Genomique). SNP genotyping data from these sequences allow the characterization of ancestral contributions from known species/subspecies, but also from two unknown ancestors.

Analyses of obtained mosaics and of introgression patterns in cultivars, allow us to propose hypotheses on the domestication and diversification process of cultivated banana.  This work also highlights the need to better characterize the wild banana diversity to identify unknown ancestors.

• Baurens, F.-C., Martin, G., Hervouet, C., Salmon, F., Yohomé, D., Ricci, S., Rouard, M., Habas, R., Lemainque, A., Yahiaoui, N., D’Hont, A. 2019. Recombination and large structural variations shape interspecific edible bananas genomes. Mol. Biol. Evol. 36, 97–111. https://doi.org/10.1093/molbev/msy199
• Martin, G., Cardi, C., Sarah, G., Ricci, S., Jenny, C., Fondi, E., Perrier, X., Glaszmann, J.C., D'Hont, A. and Yahiaoui, N. (2020) Genome ancestry mosaics reveal multiple and cryptic contributors to cultivated banana. Plant J., 102, 1008-1025. https://doi.org/10.1111/tpj.14683