Telomeric sequences distribution in nine Neotropical primates (Platyrrhinae) by (TTAGGG)n probe mapping: interstitial location and their possible role in evolution

Abstract

Platyrrhini are characterized by a high intra and intergeneric genome variability. This genome variability due to intra and inter-chromosomal rearrangements occurred during evolution could be possibly link to the involvement of telomeric and heterochromatin sequences. Telomeres, the terminal regions of chromosomes, constituted of particular repeated DNA sequences (TTAGGG)n and proteins, are called true telomeres and have their role in determining the replication and the stability of chromosomes. The DNA component of telomeres can be also found at intra-chromosomal sites such as close the centromeres and between centromere and telomeres, and are known as Interstitial Telomeric Sequences (ITSs). Traditionally considered just “junk DNA”, ITSs have been on the contrary associated with chromosomal evolution even if their role has not been yet elucidated. Chromosomal localization of ITS sequences was analyzed mapping telomeric (TTAGGG)n sequence (PNA probe) by fluorescence in situ hybridization (FISH) on: Callithrix argentata,Callithrix jacchus, Cebuella pygmaea, Saguinus oedipus, Saimiri sciureus Aotus nacymaae, Aotus lemurinus griseimembra (Cebidae), Lagothrix lagotricha (Atelidae), Callicebus moloch (Pithecidae). Telomeric sequences are localized not only at the terminal ends of all chromosomes but our results indicate that different types of ITSs (centromeric, interstitial and acrosubtelomeric) are present into three among the nine analyzed, in Lagothrix lagotricha and the two Aotus. We discuss ITSs possible role in chromosomal evolution and as potential markers in phylogenetic studies for close related species. More molecular cytogenetics studies will permit a better understanding of the mechanism of ITSs origin and contribution to chromosomal evolution in Neotropical primates.