Mapping the Distribution of the Telomeric Sequence (T sub(2)AG sub(3)) sub(n) in the 2n = 14 Ancestral Marsupial Complement and in the Macropodines (Marsupialia: Macropodidae) by fluorescence in situ hybridization

• Published in: Chromosome research Vol. 12; no. 4; pp. 405 - 414
• Main Authors: Metcalfe, C J, Eldridge, MDB, Johnston, P G
• Format: Journal Article
• Language: English
• Published: 01-05-2004
• Subjects: Macropodidae; Marsupialia
• ISSN: 0967-3849; 1573-6849
• DOI: 10.1023/B:CHRO.0000034133.77878.88

In this study we test the theory that the presence of the conserved vertebrate telomeric sequence (T sub(2)AG sub(3)) sub(n) at the centromeres of Australian marsupial 2n = 14 complements is evidence that these karyotypes are recently derived, which is contrary to the generally held view that the 2n = 14 karyotype is ancestral for Australasian and American marsupials. Here we compare the distribution of the (T sub(2)AG sub(3)) sub(n) sequence and constitutive heterochromatin in the presumed ancestral 2n = 14 complement and in complements with known rearrangements. We found that where there were moderate to large amounts of constitutive heterochromatin, the distribution of the (T sub(2)AG sub(3)) sub(n) sequence reflected its presence as a native component of satellite DNA rather than its involvement in past rearrangements. The presence of centromeric heterochromatin in all Australian 2n = 14 complements therefore suggests that centromeric sites of the (T sub(2)AG sub(3)) sub(n) sequence do not represent evidence for recent rearrangements.