title: Sexually dimorphic body color is regulated by sex-specific expression of yellow gene in ponerine ant, Diacamma sp.
abstract: Most hymenopteran species exhibit conspicuous sexual dimorphism due to ecological differences between the sexes. As hymenopteran genomes, under the haplodiploid genetic system, exhibit quantitative differences between sexes while remaining qualitatively identical, sexual phenotypes are assumed to be expressed through sex-specific gene usage. In the present study, the molecular basis for expression of sexual dimorphism in a queenless ant, Diacamma sp., which exhibits a distinct color dimorphism, was examined. Worker females of the species appear bluish-black, while winged males exhibit a yellowish-brown body color. Initially, observations of the pigmentation processes during pupal development revealed that black pigmentation was present in female pupae but not in males, suggesting that sex-specific melanin synthesis was responsible for the observed color dimorphism. Therefore, five orthologs of the genes involved in the insect melanin synthesis (yellow, ebony, tan, pale and dopa decarboxylase) were subcloned and their spatiotemporal expression patterns were examined using real-time quantitative RT-PCR. Of the genes examined, yellow, which plays a role in black melanin synthesis in insects, was expressed at higher levels in females than in males throughout the entire body during the pupal stage. RNA interference of yellow was then carried out in order to determine the gene function, and produced females with a more yellowish, brighter body color similar to that of males. It was concluded that transcriptional regulation of yellow was responsible for the sexual color dimorphism observed in this species.
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan; Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Miyazaki
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan; Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo, Japan.
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Okada
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan; Okazaki Institute for Integrative Bioscience, National Institute of Basic Biology, Okazaki, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Miyakawa
authors.affiliation: Center of Molecular Biosciences, University of the Ryukyu, Okinawa, Japan.
authors.forename: Gaku
authors.initials: G
authors.lastname: Tokuda
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan; Insect Mimetics Research Unit, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki, Japan.
authors.forename: Richard
authors.initials: R
authors.lastname: Cornette
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan; Laboratory of Molecular Biology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Koshikawa
authors.affiliation: Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.
authors.forename: Kiyoto
authors.initials: K
authors.lastname: Maekawa
authors.affiliation: Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Miura
mesh_terms: D000818:Animals; D001000:Ants / Q000235:genetics / Q000378:metabolism*; D005260:Female; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008543:Melanins / Q000096:biosynthesis / Q000235:genetics; D010858:Pigmentation / Q000502:physiology*; D012727:Sex Characteristics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D019476:Insect Proteins; D008543:Melanins; D014157:Transcription Factors