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Rapid, independent, and extensive amplification of telomeric repeats in pericentromeric regions in karyotypes of arvicoline rodents

Author:
Rovatsos, M. Th., Marchal, J. A., Romero-Fernández, I., Fernández, F. J., Giagia-Athanosopoulou, E. B., Sánchez, Antonio
Source:
Chromosome research 2011 v.19 no.7 pp. 869-882
ISSN:
0967-3849
Subject:
Arvicola, Chionomys, Microtus, chromosome morphology, evolution, fluorescence in situ hybridization, rodents, satellite DNA, telomeres
Abstract:
The distribution of telomeric repeats was analyzed by fluorescence in situ hybridization in 15 species of arvicoline rodents, included in three different genera: Chionomys, Arvicola, and Microtus. The results demonstrated that in most or the analyzed species, telomeric sequences are present, in addition to normal telomeres localization, as large blocks in pericentromeric regions. The number, localization, and degree of amplification of telomeric sequences blocks varied with the karyotype and the morphology of the chromosomes. Also, in some cases telomeric amplification at non-pericentromeric regions is described. The interstitial telomeric sequences are evolutionary modern and have rapidly colonized and spread in pericentromeric regions of chromosomes by different mechanisms and probably independently in each species. Additionally, we colocalized telomeric repeats and the satellite DNA Msat-160 (also located in pericentromeric regions) in three species and cloned telomeric repeats in one of them. Finally, we discuss about the possible origin and implication of telomeric repeats in the high rate of karyotypic evolution reported for this rodent group.
Agid:
570021