Mv. Civitelli et al., CYTOGENETICS OF THE GENUS ARVICANTHIS (RO DENTIA, MURIDAE) .1. ARVICANTHIS NILOTICUS FROM REPUBLIC OF BENIN (WEST-AFRICA), Zeitschrift fur Saugetierkunde, 60(4), 1995, pp. 215-225
Arvicanthis niloticus is characterized, according to previous karyolog
ical studies, by a wide chromosome variability. In distinct population
s of its wide area of distribution, the diploid number ranges from bet
ween 2n=44 and 2n=62. The present study analysed the karyotype of 13 A
rvicanthis niloticus from South Benin, Guinea Gulf (West Africa). The
constitutive heterochromatin pattern was evidenced by C-banding and th
e location of Nucleolar Organiser Regions was assessed by AgNO3 plus G
-banding reactions. The G-banding pattern was also performed both on c
ultured fibroblasts and bone marrow preparations. The 2n=62 and the aF
N=74 characterize the South Benin cytotype which was found to be ident
ical to that described for Southern Senegal specimens. A few chromosom
al rearrangements (3 pericentric inversions) are enough to transform t
he Benin cytotype into the ANI-3 cytotype described in animals from Ma
ll and Burkina Faso. A polymorphism of the X chromosome is described;
three different forms (i.e. metacentric, submetacentric, and subteloce
ntric) were observed both in homomorphic and heteromorphic conditions.
The problem of intraspecies chromosomal variability in Arvicanthis ni
loticus is discussed.