Dociostaurus jagoi and Dociostaurus genei are two acridoid grasshopper
s which show large differences in heterochromatin content. The use of
several banding techniques, including fluorochrome staining and restri
ction endonuclease digestion, provides further information on the char
acteristics of the constitutive heterochromatin regions revealed with
the C-banding method. Thus both species show GC-enriched bands accompa
nying active nucleolar organizers which differ in location. Because of
its bright response to DAPI and CMA3, the centromeric heterochromatin
seems to have a bipartite nature in terms of DNA composition in D. ge
nei, while it shows dull staining with both fluorochromes in D. jagoi.
However, two endonucleases, MboI and Sau3A, extensively digest these
regions in both species. The supernumerary heterochromatic segments pr
esent only in D. genei seem to be AT-rich and are extensively digested
with AluI. These results reveal heterogeneity in the distinct C-bande
d regions which, in turn. are equilocally distributed in both chromoso
me complements.