ABSTRACT
C-bands are detectable in any eukaryote taxon. Generally the size and position of the C-bands are very good chromosome markers in karyological studies and are particularly useful in karyotyping taxa (like fi shes) in which G-, R-and Q bands cannot normally be induced (Sumner 1990). In a normal karyotype at least a small band is usually present at the centromere of chromosomes and pericentromeric, telomeric and sometimes intercalary bands are found (Fig. 1). C-bands can be heteromorphic in many species and the heteromorphisms
can be found among individuals and among populations of the same species. Moreover, C-bands are useful markers in karyotype evolutionary studies. In fact, differences in constitutive heterochromatin amount and localization are often found among related species.
