the amelogenin gene, amel, encodes an important protein for tooth enamel formation during development. it is highly conserved among mammals. the amel gene, which is located in sex chromosomes in humans, exhibits a length polymorphism for the x and y copies of the gene. this length polymorphism has been reported in several mammal species, and the differences between the x and y chromosomes are used for sex determination by amplifi cation of the polymorphic regions. in this work, we analyzed amel in akodon azarae and lagostomus maximus. in order to assess the identity of the individuals and verify the presence or absence of chromosomal rearrangements, a cytogenetic study was performed. to amplify the amel region, specifi c primers were designed using the genomic information of rattus norvegicus, mus musculus and humans. the sequenced pcr product confi rmed the presence of the amel region in both species obtaining, for the fi rst time, a partial sequence for the gene in the subject species. this sequence would be homologous to the amelogenin intron 3 in r. norvegicus and m. musculus. the future sequencing of the full length gene and the possibility to differentiate between x and y in a. azarae and l. maximus is our next objective.