Mutator-like transposase is the most represented transposon transcript in the sugarcane transcriptome. Phylogenetic reconstructions derived from sequenced transcripts provided evidence that at least four distinct classes exist (I- IV) and that diversification among these classes occurred early in Angiosperms, prior to the divergence of Monocots/ Eudicots. The four previously described classes served as probes to select and further sequence six BAC clones from a genomic library of cultivar R570. A total of 579,352 sugarcane base pairs were produced from these "Mutator system" BAC containing regions for further characterization. The analyzed genomic regions confirmed that the predicted structure and organization of the Mutator system in sugarcane is composed of two true transposon lineages, each containing a specific terminal inverted repeat and two transposase lineages considered to be domesticated. Each Mutator transposase class displayed a particular molecular structure supporting lineage specific evolution. MUSTANG, previously described domesticated genes, are located in syntenic regions across Sacharineae and, as expected for a host functional gene, posses the same gene structure as in other Poaceae. Two sequenced BACs correspond to hom(eo)logous locus with specific retrotransposon insertions that discriminate sugarcane haplotypes. The comparative studies presented, add information to the Mutator systems previously identified in the maize and rice genomes by describing lineage specific molecular structure and genomic distribution pattern in the sugarcane genome. (Résumé d'auteur)