A method for the molecular characterization of bbl loci in Drosophila melanogaster

Summary In this work we have used a method that allows a rapid and precise quantification of rRNA genes. With the purpose of examining small numbers of rRNA genes, we used Drosophila melanogaster embryos which are inviable because their sex chromosomes carry extensive rDNA deletions. Two of the mutants, B^sYbb¹ and Ybb^l, appear to be completely devoid of rDNA. The third, Ybb^-, contains no more than five genes.Work supported by C.N.R. contract No. 82-2100 and Progetto Finalizzato C.N.R. Ingegneria Genetica No. 83-01007-51