Chromosomal polymorphism in the rodent Akodon arviculoides ssp. (2n-14) resulting from two pericentric inversions.

Abstract

Eight specimens of Akodon arviculoides ssp. (four males and four females), collected in the state of Sao Paulo, Brazil, were studied. All seven pairs of chromosomes were identifiable. Two specimens had an heteromorphic pair of autosomes apparently resulting from a pericentric inversion (pair 3, with a metacentric and an acrocentric chromosome). Two other specimens possessed, in addition to this same inversion, another inversion in pair 2. The four remaining specimens had no heteromorphic pairs of chromosomes; pair 3 was acrocentric in two of them and metacentric in the other two. The measurements of mitotic chromosomes and the analysis of meiosis were compatible with the hypothesis of pericentric inversions.