Swallowtail butterfly tiger swallowtail), Y-linkage determines whether the females are either wild-type (yellow and black) or melanic (dark melanin replaces the yellow background). This genetic difference stems from the fact that melanism is controlled by a single gene, which controls the level of dopamine in the organism. The enzyme BAS, which assists dopamine in producing the yellow pigmentation, normally found on the wings' background, is suppressed. Without the pigmentation, the butterfly appears mostly black (the melanic form) and is a Batesian mimic of "Battus philenor", the pipevine swallowtail. There are also "Papilio glaucus" that are not wholly black; several possess an intermediate
Pythagorean comma cycle of perfect fifths were continued beyond 12 all the way to 53, the difference between this 53rd pitch and the starting pitch would be much smaller than the Pythagorean comma. This much smaller interval was later named Mercator's comma ("see: history of 53 equal temperament"). In George Russell's "Lydian Chromatic Concept of Tonal Organization" (1953) the half step between the Lydian Tonic and 2 in his Altered Major and Minor Auxiliary Diminished Blues scales is theoretically based on the interval of a Pythagorean comma. Pythagorean comma In musical tuning, the Pythagorean comma (or ditonic comma), named after the ancient