FACTORS INFLUENCING DISPROPORTIONATE REPLICATION OF THE RIBOSOMAL RNA CISTRONS IN DROSOPHILA MELANOGASTER

F. Lee Dutton ¹ and Hallie M. Krider ¹

¹ Biological Sciences Group, Genetics, Cellular and Molecular Biology Section, The University of Connecticut, Storrs, Connecticut 06268

This report describes studies of the compensatory response employing D. melanogaster stocks that bear cloned-X chromosomes derived from laboratory populations of strains Oregon R and Canton S. We find that modification of the autosomal background in either the female or the (see PDF) male parent influences the expression of the compensatory response by X chromosomes derived from the Canton S population, whereas Oregon R isolates are unresponsive to these effects. We have also studied compensatory replication in X/O larvae produced from cloned-X derivatives of both Canton S and Oregon R. Canton S larval compensation exceeds that of the adult, whereas in Oregon R the converse is true. We have concluded that both X chromosomal and autosomal factors affect the expression and magnitude of the compensatory response.