Relative orientation with respect to the centromere of ribosomal RNA genes of the X and Y chromosomes of Drosophila melanogaster.
We tested for recombination within the DNA that codes for ribosomal RNA (rDNA) on the X and Y chromosomes of Drosophila melanogaster. The criterion was the appearance of intermediate bb alleles on X-Y recombinants from wild bb(+) and lethal bb(1) loci carried on parental chromosomes. Recombination within the rDNA occurs only when the rDNA of the X chromosome is inverted. We conclude that rDNAs of normal X and Y chromosomes have opposite orientation with respect to the centromere. The implications of this observation are discussed.
D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D004331:Drosophila melanogaster; D005260:Female; D008297:Male; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D011995:Recombination, Genetic; D012730:Sex Chromosomes
D012335:RNA, Ribosomal