title: Pigment cell mechanisms underlying dorsal color-pattern polymorphism in the Japanese four-lined snake.
abstract: To provide histological foundation for studying the genetic mechanisms of color-pattern polymorphisms, we examined light reflectance profiles and cellular architectures of pigment cells that produced striped, nonstriped, and melanistic color patterns in the snake Elaphe quadrivirgata. Both, striped and nonstriped morphs, possessed the same set of epidermal melanophores and three types of dermal pigment cells (yellow xanthophores, iridescent iridophores, and black melanophores), but spatial variations in the densities of epidermal and dermal melanophores produced individual variations in stripe vividness. The densities of epidermal and dermal melanophores were two or three times higher in the dark-brown-stripe region than in the yellow background in the striped morph. However, the densities of epidermal and dermal melanophores between the striped and background regions were similar in the nonstriped morph. The melanistic morph had only epidermal and dermal melanophores and neither xanthophores nor iridophores were detected. Ghost stripes in the shed skin of some melanistic morphs suggested that stripe pattern formation and melanism were controlled independently. We proposed complete- and incomplete-dominance heredity models for the stripe-melanistic variation and striped, pale-striped, and nonstriped polymorphisms, respectively, according to the differences in pigment-cell composition and its spatial architecture.
authors.affiliation: Department of Biology, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba, 274-8510, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Kuriyama
authors.forename: Hanae
authors.initials: H
authors.lastname: Misawa
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Miyaji
authors.forename: Masazumi
authors.initials: M
authors.lastname: Sugimoto
authors.forename: Masami
authors.initials: M
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D002452:Cell Count; D003116:Color; D017812:Colubridae / Q000033:anatomy & histology* / Q000235:genetics; D020405:Dermis / Q000166:cytology; D000078404:Epidermal Cells; D007564:Japan; D008547:Melanophores / Q000166:cytology*; D009024:Morphogenesis; D010858:Pigmentation / Q000235:genetics
keywords: color polymorphism; heredity mode; pigment cells; snake