HETEROCHROMATIN DIFFERENTIATION BETWEEN 2 SPECIES OF THE GENUS DOCIOSTAURUS (ORTHOPTERA, ACRIDIDAE)

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.