Intraspecific variation in the distribution of the interstitial telomeric (TTAGGG)(n) sequences in Micoureus demerarae (Marsupialia : Didelphidae)

The distribution of the telomeric sequence (TTAGGG)(n) was studied in chrom osomes of Micoureus demerarae (2n=14), a South American marsupial, by fluor escence in-situ hybridization (FISH). The telomeric repeat sequence was pre sent at both ends of all chromosomes, but also various interstitial telomer ic sequences (ITS) were detected in the pericentromeric heterochromatic reg ions. Intraspecific differences in the number of ITS (2 to 8) were observed without intraindividual variation. The presence of telomere-like sequences in the same regions of constitutive heterochromatin suggest that these seg ments are not necessarily remnants of true telomeres resulting from chromos ome rearrangements but could be part of the satellite DNA.