A Molecular Explanation of the Bobbed Mutants of Drosophila as Partial Deficiencies of "Ribosomal" Dna

I N this paper we offer an explanation of the genetic feature known in Drosophila as bobbed (bb) . Experiments will be described in which DNA preparations from flies carrying various bb alleles were assayed for their content of the special DNA ("ribosomal"-DNA) that forms molecular hybrids with Drosophila ribosomal RNA. In view of the differences found between bb and wild type, and the special role attributed to this DNA, rather coherent relations appear among long-known characteristics of bb. At the outset we review these characteristics, since each has some degree of relevance to the explanation to be developed. * It has been pointed out by J.~cK SCHULTZ (personal communication) that this may represent a Y-translocation linked to a "Minute".