Evolutionary conservation of whole homeologous chromosome arms in the Akodont rodents Bolomys and Akodon (Muridae, Sigmodontinae): maintenance of interstitial telomeric segments (ITBs) in recent event of centric fusion

We have identified the almost complete correspondence of whole chromosome a rms between the karyotypes of Bolomys lasiurus (2n = 33, 34) and Akodon mon tensis (2n = 24, 25) using comparative analysis of the GTG-banding patterns . To explain the karyotypic differentiation of the species, tandem and cent ric fusions, pericentric inversions, loss of telomeres and centromeres are required. Localization of telomere sequences using an (TTAGGG)(n) oligomere as a fluorescence in situ hybridization probe provided evidence of the mai ntenance of interstitial telomere sequences in a polymorphic centric fusion of recent origin in Bolomys lasiurus. The homeologies shared between the c hromosomes of these two species and those of A. cursor (2n = 16), from prev ious work, are discussed.