ISSN:
1573-6857
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Chromosomes were analyzed in 91 specimens ofNectomys squamipes, collected in three distinct geographic regions of Brazil. Chromosomal polymorphism due to supernumerary chromosomes, Robertsonian rearrangement and variation of sex chromosomes is reported. Samples collected in the northeastern region had 2n=52, FN=52; 2n=53, FN=54; 2n=54, FN=56; 2n=55, FN=56; 2n=56, FN=56; 2n=57, FN=57. The specimens from the southeastern and southern regions showed 2n=55, FN=56; 2n=56, FN=56; 2n=57, FN=58; 2n=58, FN=60; 2n=59, FN=62. Seven different types of supernumeraries were observed. These vary in size, morphology and C-banding characteristics. The Brazilian populations ofNectomys squamipes are composed of at least two basic entities, one with 2n=52 and its increasing series up to 2n=55, the other with 2n=56, increasing to 2n=59. Both entities are characterized by variation from 0 to 3 supernumeraries. The X and Y chromosomes present polymorphisms in terms of the size, shape as well as the distribution of constitutive heterochromatin.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00605896
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