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
Comma splice poetic, dashing. Done equally knowingly by people who are not published writers, it can look weak or presumptuous. Done ignorantly by ignorant people, it is awful". Comma splice In English grammar, a comma splice or comma fault is the use of a comma to join two independent clauses. For example: The comma splice is sometimes used in literary writing to convey a particular mood of informality. Otherwise, it is usually considered an error in English writing style. Some authorities on English usage consider comma splices appropriate in limited situations, such as informal writing or with short similar phrases. Comma splices