In molecular biology, Sphinx (spx) is a long non-coding RNA found in Drosophila . It is expressed in the brain, within the antennal lobe and inner antennocerebral tract. [1] It is involved in the regulation of male courtship behaviour, this may be via olfactory neuron mediated regulation. Sphinx may act as a negative regulator of target genes. [1] [2] It is a chimeric gene, originating from a retroposed sequence of the ATP synthase chain F gene from chromosome 2 to chromosome 4. Nearby sequences were recruited to form an intron and an exon of this chimeric gene. [3]