Chromosomal variation in Argentine populations of Akodon montensis Thomas, 1913 (Rodentia, Cricetidae, Sigmodontinae)

MATÍAS MAXIMILIANO MALLERET; CAROLINA ALICIA LABARONI; GABRIELA VERÓNICA GARCÍA; JUAN MARTÍN FERRO; DARDO ANDREA MARTÍ; CECILIA LANZONE

COMPARATIVE CYTOGENETICS

ZOOLOGICAL INST

Año: 2016

1993-0771

The Akodon genus Meyen, 1833is one of the most species-rich among sigmodontine rodents and has greatchromosome variability. Akodon montensis hasa relatively broad distribution in South America, and Argentine populations arelocated in the southernmost region of its range. Brazilian populations have importantchromosomal variability, but the cytogenetic data from Argentina are scarce. Weperformed a chromosome characterization of natural population of A. montensis using conventionalstaining, C-banding, Ag-NORsand base-specific fluorochromes. A total of 31 specimens from five localitiesof Misiones Province, in Argentina, were analyzed. The 2n=24 chromosomes was themost frequently observed karyotype. However, five individuals presented 25chromosomes due to a supernumerary B-chromosome; and one individual had 2n=26 dueto one B plus a trisomy for chromosome 11. Additionally, one XY female and twovariants of the X chromosomes were found. C-positive centromeric bands occurredin all chromosomes; additional C-bands were observed in some autosomes, the X,Y and B chromosomes. Ag-NORs were observed in five autosomes, and the Bchromosome was frequently marked. Fluorochrome banding was similar among karyotypesof the analyzed populations. Comparisons of cytogenetic data among populationsof Argentina and Brazil showed the presence of high intraspecific variabilityin A. montensis and some differencesamong regions.