Characterization of translocations in banana by FISH Of BAC clones anchored to a genetic map
2006
Vilarinhos, Alberto | Carreel, Françoise | Rodier, Marguerite | Hippolyte, Isabelle | Benabdelmouna, Abdellah | Triaire, Dolorès | Bakry, Frédéric
Chromosome pairing at meiosis revealed that translocations are frequent in banana genomes. In Musa acuminata, the main species involved in banana cultivars, seven groups of accessions have been identified on the basis of the patterns of translocations ("Standard": which likely represents the ancestral configuration, and North Malaysia, Malaysia Mountains, North A, North B, Indonesia, and East Africa). These translocations make difficult to construct genetic map, to study agronomical characters inheritance and to breed in general. In order to initiate the characterization of the translocations between the accessions 'Calcutta 4' (2n=2x=22, translocation group North A) and 'Madang' (2n=2x=22, translocation group Standard), we developed FISH of BAC clones anchored to a genetic map. This map was built based on an F2 population from 'Calcutta 4' x 'Madang', it encompasses 244 markers (19RFLP, 47 SSR, 178 AFLP) distributed in 13 linkage groups. A 'Calcutta 4' BAC library representing a 10x coverage of this genome was constructed. Linkage group II (LGII) was chosen to search for translocations since some of its features, such as the high number of distorted markers, the group size and comparison with others banana maps, suggested that this group involved several chromosomes bearing translocations. Four BAC clones corresponding to 3 RFLP and 1 SSR loci distributed on LG II were localized on the 'Calcutta 4' and 'Madang' chromosomes. The results show that the markers involved in this LG are located on three different chromosomes, whose structure differs being different between the two parent by the presence of the two linked translocations in 'Calcutta 4' in relation to the "standard" reference Madang. (Texte intégral)
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