Chromosome reciprocal translocations have accompanied subspecies evolution in bananas

DATA AVAILABILITY STATEMENT: The VCF files, specific allele list, and genetic mapping matrices are available in the download section of the Banana Genome Hub (http://banana-genomehub.southgreen.fr). The Illumina data of the 11 progenies are available in the SRA database under project PRJNA667853. The raw whole genome sequencing illumina from the 155 accessions analyzed during the present study are not publicly available because they are part of a larger ongoing project, although they are available from the corresponding author on reasonable request.

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anglais. Chromosome rearrangements and the way that they impact genetic differentiation and speciation have long raised questions from evolutionary biologists. They are also a major concern for breeders because of their bearing on chromosome recombination. Banana is a major crop that derives from inter(sub)specific hybridizations between various once geographically isolated Musa species and subspecies. We sequenced 155 accessions, including banana cultivars and representatives of Musa diversity, and genotyped-by-sequencing 1059 individuals from 11 progenies. We precisely characterized six large reciprocal translocations and showed that they emerged in different (sub)species of Musa acuminata, the main contributor to currently cultivated bananas. Most diploid and triploid cultivars analyzed were structurally heterozygous for 1 to 4 M. acuminata translocations, highlighting their complex origin. We showed that all translocations induced a recombination reduction of variable intensity and extent depending on the translocations, involving only the breakpoint regions, a chromosome arm, or an entire chromosome. The translocated chromosomes were found preferentially transmitted in many cases. We explore and discuss the possible mechanisms involved in this preferential transmission and its impact on translocation colonization.