SciELO - Scientific Electronic Library Online

vol.30 issue1Genetic characterization of the Spanish Trotter horse breed using microsatellite markersChromosome study in Schistocerca (Orthoptera-Acrididae-Cyrtacanthacridinae): karyotypes and distribution patterns of constitutive heterochromatin and nucleolus organizer regions (NORs) author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand




Related links


Genetics and Molecular Biology

Print version ISSN 1415-4757On-line version ISSN 1678-4685


PARESQUE, Roberta; SILVA, Maria José de Jesus; YONENAGA-YASSUDA, Yatiyo  and  FAGUNDES, Valéria. Karyological geographic variation of Oligoryzomys nigripes Olfers, 1818 (Rodentia, Cricetidae) from Brazil. Genet. Mol. Biol. [online]. 2007, vol.30, n.1, pp.43-53. ISSN 1415-4757.

The karyotypes of 85 specimens of Oligoryzomys nigripes (Rodentia, Sigmodontinae) collected in the Cerrado and Atlantic Forest of seven states of Brazil were analyzed. Eighty four specimens presented a karyotype with 2n = 62 and one individual had 2n = 61 due to a monosomy of the X chromosome. High levels of intra- and inter-population karyotypic variability, due to sex chromosomes heteromorphisms and pericentric inversions in four autosomes (pairs 2, 3, 4 and 8), led to a variation of the autosomal arm numbers (fundamental number, FN) from 78 to 82. Synaptonemal complex analyses revealed normal meiosis in males heterozygous for pericentric inversions. We found 39 different cytotypes, 27 of which are herein described for the first time. A literature survey revealed 46 described karyotypes for O. nigripes. We tested the hypothesis that chromosomal variants frequencies are dependent on geographical distribution and we propose a model for the karyotypical evolution of Oligoryzomys nigripes with 2n = 62/FN = 78-82.

Keywords : pericentric inversion; Oryzomyini; Oligoryzomys nigripes; Rodentia; clinal variation.

        · text in English     · English ( pdf epdf )


Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License