Function and misfunction of the two promoters of the Drosophila Antennapedia gene

In the Antennapedia (Antp) gene of Drosophila melanogaster, structurally distinct RNAs arise from different transcription initiation sites. When the two sites are separated by a chromosome inversion, transcripts are produced from each fragment of the split Antp locus, and these RNAs initiate at the same nucleotide as in wild-type animals. Thus, the initiation sites are regulated by independent promoters.