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
Syntonic comma amount by which Didymus corrected the Pythagorean major third (81:64, around 407.82 cents) to a just major third (5:4, around 386.31 cents). The word "comma" came via Latin from Greek κόμμα, from earlier *κοπ-μα = "an act of cutting". The prime factors of the just interval 81/80 known as the syntonic comma can be separated out and reconstituted into various sequences of two or more intervals that arrive at the comma, such as 81/1 * 1/80 or (fully expanded and sorted by prime) 1/2 * 1/2 * 1/2 * 1/2 * 3/1 * 3/1 * 3/1 *3/1 * 1/5. All