Heterochromatin differentiation between two species of the genus dociostaurus (Orthoptera: Acrididae)

Abstract

Dociostaurus jagoi and Dociostaurus genei are two acridoid grasshoppers which show large differences in heterochromatin content. The use of several banding techniques, including fluorochrome staining and restriction endonuclease digestion, provides further information on the characteristics of the constitutive heterochromatin regions revealed with the C-banding method. Thus both species show GC-enriched bands accompanying 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. genei, while it shows dull staining with both fluorochromes in D. jagoi. However, two endonucleases, Mbol and Sau3A, extensively digest these regions in both species. The supernumerary heterochromatic segments present only in D. genei seem to be AT-rich and are extensively digested with Alul. These results reveal heterogeneity in the distinct C-banded regions which, in turn, are equilocally distributed in both chromosome complements. © 1993 The Genetical Society of Great Britain.