Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837) (RODENTIA, CRICETIDAE, SIGMODONTINAE)

LABARONI CA; MALLERET MM; NOVILLO AGUSTINA; OJEDA AGUSTINA; RODRÍGUEZ DANIELA; CUELLO, PABLO; OJEDA RICARDO ALBERTO; LANZONE CECILIA

COMPARATIVE CYTOGENETICS

ZOOLOGICAL INST

Año: 2014

1993-0771

Phyllotis xanthopygus is an Andean rodent endemic to South America. Chromosome characterization of Argentine samples of this species was performed using conventional staining, C-banding, base-specific fluorochromes and meiotic preparations. In this work, twenty two specimens were analyzed, collected in Jujuy (N=4), Catamarca (N=4), and north (N=4) and south of Mendoza (N=10). All studied specimens showed 2n=38, with most of the autosomes being metacentric or submetacentric. Some differences are observed that produce variations in the FN from 70 to 72. These changes are due to the presence of chromosome heteromorphisms in southern Mendoza and Jujuy Provinces. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3) revealed relatively high homology among chromosomes of the different populations analyzed. On the other hand, the homology among heteromorphic pairs suggested that these are the result of complex chromosome rearrangements, involving at least a pericentric inversion and heterochromatin addition. These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.