Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae)

LABARONI C; MALLERET M; A. NOVILLO; OJEDA A; D. RODRÍGUEZ; P. CUELLO; R.A.OJEDA; MARTÍ D. A.; LANZONE C

COMPARATIVE CYTOGENETICS

ZOOLOGICAL INST

Año: 2014 vol. 8 p. 369 - 381

1993-0771

Phyllotis xanthopygus Waterhouse, 1837 is an Andean rodent endemic to South America. Despite its wide geographical distribution in Argentina, few individuals were studied at cytogenetic level and only through conventional staining. In this work chromosome characterization of Argentine samples of this species was performed using conventional staining, C-banding, base-specific fluorochromes and meiotic preparations. Twenty two specimens were analyzed, collected in provinces of Jujuy, Catamarca, and north and south of Mendoza. All studied specimens showed 2n=38, with most of the autosomes being metacentric or submetacentric. Some differences were observed that produce variations in the FN from 70 to 72. These changes were due to the presence of chromosome heteromorphisms in dividuals from southern Mendoza and Jujuy. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in the amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3) revealed relatively high homology among chromosomes ofthe 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 inversionand heterochromatin addition.These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.