Chromosomal map of the RP genes of D. melanogaster. RP genes are depicted on a physical map of the genome (Release 5) . Genes encoded on the positive and negative strands are shown above and below the chromosome, respectively. (The orientation of RpL15 is not known and its position below the chromosome is arbitrary.) Chromosomes are divided into cytological bands as determined from sequence-to-cytogenetic band correspondence tables . Minute genes are boxed as described in the key.