The volume and DNA content of extrachromosomal inclusions in the dorsal foot-pad nuclei of Tricholioproctia impatiens (Sarcophagidae, Diptera).

The chromosomes of the giant dorsal foot-pad cells of Tricholioproctia impatiens produce numerous extrachromosomal bodies which consist of a central spherical core of DNA surrounded by a ribonucleoprotein layer. The bodies are either free within the nucleoplasm or attached by thin threads of chromatin to chromosomal bands. The DNA content and the volume of DNA of unattached spherules fell into distinct classes in a regular geometric progression.