Distribution of Telomeric Sequences (TTAGGG)n in Rearranged Chromosomes of Phyllotine Rodents (Cricetidae, Sigmodontinae)

LANZONE, C.; LABARONI, C.; SUÁREZ, S.; RODRÍGUEZ, D.; HERRERA, M.; BOLZAN, A.

CYTOGENETIC AND GENOME RESEARCH

KARGER

Lugar: Basel; Año: 2016 vol. 147 p. 247 - 252

1424-8581

Phyllotine are sigmodontine rodents endemic to South America with broad genetic variability, being Robertsonian polymorphisms the most frequent. Moreover, this taxon includes a species with multiple sex chromosomes, which is infrequent in mammals. However, molecular cytogenetic techniques were never applied to phyllotines to study its karyotypic evolution. We study the chromosome of four phyllotine species using FISH with a pantelomeric probe (TTAGGG)n. Graomys griseoflavus, Eligmodontia puerulus and E. morgani are polymorphic for Robertsonian translocations; whereas Salinomys delicatus posses XX/XY1Y2 sex chromosomes. Telomeric signals were detected at both ends of all chromosomes of studied species. In S. delicatus interstitial telomeric sequences (ITS) were observed in the three major chromosome pairs, which are equidistant from one of the telomeres in these chromosomes. These results suggest that ITS are important in the reshuffling of the highly derived karyotype of S. delicatus. Considering the phylogeny of phyllotines, the Robertsonian rearrangements of G. griseoflavus, E. puerulus and E. morgani possibly represent chromosome fusions which have occurred independently. The pericentromeric regions of the biarmed chromosomes of these species do not contain the telomeric sequences characteristic of strict fusions of recent origin, suggesting a common pattern of telomeric repeats loss during the chromosomal evolution of these rodents.