Ultraviolet and violet receptors express identical mRNA encoding an ultraviolet-absorbing opsin: Identification and histological localization of two mRNAs encoding short-wavelength-absorbing opsins in the retina of the butterfly Papilio xuthus

This paper describes the primary structures of two opsins of short-waveleng th-absorbing visual pigments deduced from the mRNA sequences in the retina of the Japanese yellow swallowtail butterfly Papilio xuthus. A phylogenetic analysis of the amino acid sequences indicates that one of these visual pi gments is of the ultraviolet-absorbing type and that the other is of the bl ue-absorbing type. We identified the photoreceptor cells that express these mRNAs by histological in situ hybridization. The mRNA of the ultraviolet t ype is expressed in two distinct photoreceptor types previously identified as ultraviolet and violet receptors, providing the first molecular biologic al evidence that different types of spectral receptor probably express a vi sual pigment with an identical amino acid sequence. The mRNA of the blue ty pe is expressed exclusively in cells classified as blue receptors.