Sugarcane cultivars (Saccharum spp.) present one the most complex crop genomes studied to date: highly polyploids (more than decaploids) and aneuploids, with around 120 chromosomes and a genome size of around 10 Gb. In order to investigate the organisation of this highly polyploid genome (% of homology between allele haplotypes, content in repeated sequence...), which is essential for elaborating a whole genome sequencing strategy, we sequenced and compared seven hom(oe)ologous haplotypes (BAC clones) from the sugarcane cultivar R570. These haplotypes showed a very high colinearity as well as very high gene structure and sequence conservation. A high homology was also observed along the non-transcribed regions to the exception of transposable elements (TEs) which represents between 18 and 53% of the BAC sequence. A high colinearity was also observed in the overlapping regions between sugarcane and sorghum and to a lower extent with rice. (Texte intégral)