A RARE CASE OF CHROMOSOMAL MUTATION IN TH E GROUND VOLE, TERRICOLA-MAJORI (ARVICOLINAE, RODENTIA)

A rare case of chromosome variability is described for the ground vole , Terricola majori, from the Lagodekhi Nature Reserve (Georgia). This species is characterized by a stable karyotype (2n = 54, NF = 60), but we found an animal in which 2n = 53, NF = 60. The change in the diplo id number resulted from a Robertsonian translocation accompanied by a local amplification of satellite sequences in centromeric heterochroma tin. This structural rearrangement is probably a neutral mutation and is described for forest T. majori voles for the first time.