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 chromosomes of Micoureus demerarae (2n = 14), a South American marsupial, by fluorescence in-situ hybridization (FISH). The telomeric repeat sequence was present at both ends of all chromosomes, but also various interstitial telomeric sequences (ITS) were detected in the pericentromeric heterochromatic regions. 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 segments are not necessarily remnants of true telomeres resulting from chromosome rearrangements but could be part of the satellite DNA.