Most cultivated bananas are derived from natural hybridization between subspecies of Musa acuminata and some with Musa balbisiana. On the basis of chromosome pairing patterns at meiosis in inter-subspecies hybrids, it has been suggested that the genomes of M. acuminata subspecies differ by large chromosomal rearrangements.
These differences in chromosome structure are thought to impact chromosome segregation and thus traits of agronomic interest, as well as fertility. However, little is known about their precise nature, their distribution in banana diversity and the extent of the genomic areas involved.
The production of a banana reference sequence coupled with new sequencing technologies has allowed us to access a new level of resolution to characterize these structural differences. In this context, we have developed an approach combining genetic mapping data from genotyping by sequencing, comparative genomics from paired sequences and BAC-FISH.
We have identified and characterized seven reciprocal translocations and one inversion in different Musa species and subspecies of Musa acuminata. Analysis of chromosome segregation in individuals heterozygous for these translocations revealed that they induce recombination reductions of variable intensity involving breakpoints, chromosome arms or entire chromosomes. On the other hand, they induce important segregation distortions and translocated chromosomes are often preferentially transmitted.

Analysis of the distribution of these translocations in diversity has allowed hypotheses to be made about the pools of banana diversity in which they have emerged.

The characterization of these structural variations and their impact on chromosome segregation and recombination will now make it possible to take them into account for the genetic analysis of traits of agronomic interest (QTL, GWAS) and eventually for the choice of crosses in breeding programs.

•  Martin G, Baurens F-C, Hervouet C, Salmon F, Delos J-M, Labadie K, Perdereau A, Mournet P, Blois L, Dupouy M, et al. 2020. Chromosome reciprocal translocations have accompanied subspecies evolution in bananas. Plant J. 104:1698–1711 https://doi.org/10.1111/tpj.15031 
• 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
• Dupouy, M., Baurens, F.-C., Derouault, P., Hervouet, C., Cardi, C., Cruaud, C., Istace, B., Labadie, K., Guiougou, C., Toubi, L., Salmon, F., Mournet, P., Rouard, M., Yahiaoui, N., Lemainque, A., Martin, G., D’Hont, A. 2019. Two large reciprocal translocations characterized in the disease resistance-rich burmannica genetic group of Musa acuminata. Ann. Bot. 124, 319–329. https://doi.org/10.1093/aob/mcz078
• Martin, G., Carreel, F., Coriton, O., Hervouet, C., Cardi, C., Derouault, P., Roques, D., Salmon, F., Rouard, M., Sardos, J., Labadie, K., Baurens, F.-C., D’Hont, A. 2017. Evolution of the banana genome (Musa acuminata) is impacted by large chromosomal translocations. Mol. Biol. Evol. 34, 2140–2152. https://doi.org/10.1093/molbev/msx164