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Squire, R. D.

Publications and source records attributed to Squire, R. D..

4 recordsLinked to original sources

The Cellular Expression and Genetics of an Established Polymorphism in Poecilia reticulata; Purple Body, (Pb) is an Autosomal Dominant Gene

Modification of wild-type carotenoid orange and pteridine red coloration and spotting of male ornaments in both wild populations of Poecilia reticulata (Guppies) and modern Domestic Guppy strains by the Purple Body gene has long been overlooked in research articles and little understood in breeder publications. This modification is commonly found in wild-type Poecilia reticulata reticulata populations from numerous collection sites and has been photographed but not recognized in these collections. It is non-existent or near absent in collections taken from variant populations of Poecilia reticulata wingei. We identify and determine the mode of inheritance, cellular and phenotypic expression by the Purple gene in these stocks. The Purple Body color pigment modification is a distinct polymorphism in wild P. reticulata reticulata populations. Its existence suggests multiple benefits that satisfy female sexual selection preferences, and minimize or reduce potential predation risks. Photographic and microscopic evidence demonstrated that Purple Body is a normal polymorphism in wild and domestic guppies modifying color pigment regions. Purple Body is inherited as an autosomal incompletely dominant trait.

evolutionary biology

The Cellular Expression and Genetics of Purple Body (Pb) in Poecilia reticulata, and its Interactions with Asian Blau (Ab) and Blond (bb) under Reflected and Transmitted Light

Mature Purple Body and Non-Purple Body male guppies differ from each other in several ways. Non-Purple males may have large numbers of xanthophores, erythrophores, and blue iridophores, in addition to the usual dendritic, corolla and punctate melanophores. Fewer violet iridophores are found. In contrast, homozygous Purple Body males lack collected and clustered xanthophores, although isolated single xanthophores remain. Violet iridophores and blue iridophores (violet-blue chromatophores units) abound. The dendrites of dendritic melanophores are finer and form chains with each other. Punctate and corolla melanophores in areas comprising orange ornaments are greatly reduced in number. The heterozygous Purple Body male has erythrophores similar to those of non-Purple males, but yellow pigment is reduced. The melanophores are not as greatly changed in orange ornaments. In Domestic Guppy strains, and at least in one suspected instance in wild-type, melanophore structure and populations may be further modified by one or more additional autosomal genes.

evolutionary biology

The Cellular Expression and Genetics of Purple Body (Pb) in the Ocular Media of the Guppy Poecilia reticulata

Our study revealed the presence of all major classes of chromatophores (melanophores, xanthophores, erythrophores, violet-blue iridophores, xantho-erythrophores) and crystalline platelets in various combinations in the iris and ocular media (cornea, aqueous humor, vitreous humor, outer lens membrane) of Poecilia reticulata. This novel ocular media study of P. reticulata takes into account the distinct interactions of Purple Body (Pb) based on results of previous Bias and Squire Purple Body (Pb) publications. Taken in conjunction with other researchers published results (regarding UV reflected color and pattern, vision, mate choice, individual preferences, and opsin capabilities) this indicates that these ocular chromatophore populations together create a complex ocular filter mechanism. This mechanism in turn provides spectral capabilities into the UV and Near-UV wavelengths in both Pb and non-Pb individuals. The chromatophores in the cornea, aqueous humor, covering membranes of the lens, and the vitreous humor comprise an ocular filter system that could reduce UV damage to the internal structures of the eye. The guppys ability to use UVA as a visual component provides a \"private signally system\" that cannot be detected by some predators. While non-Pb guppies should derive benefit in the near-UV from violet-blue iridophore units, greater benefit will be derived by Pb individuals with more violet iridophores functioning in the lower UV and near-UV wavelengths. To our knowledge little has been published for P. reticulata concerning pigmentation within the guppy eye. Macroscopic and microscopic imagery is presented.

evolutionary biology

The Phenotypic Expression of Purple Body (Pb) in Domestic Guppy Strains of Poecilia reticulata

Modification of wild-type carotenoid orange and pteridine red coloration and spotting of male ornaments in modern Domestic Guppy Strains (Poecilia reticulata reticulata) by the naturally occurring Purple Body gene (Pb) has been long incorporated into their strains by Pedigree Stock Breeders. It is inherited as an autosomal incompletely dominant trait. Its existence has allowed breeders to produce a vast array of Purple based phenotypes. Photographic evidence demonstrates that Purple Body is a normal polymorphism in domestic guppies modifying color pigmented regions. When combined with currently used mutant genes such as Albino, Blond, Golden, Asian Blau, Coral Red, Magenta, Grass, Moscow, Pink, Platinum, Red Mosaic, Multicolor, and Full Red, startling new phenotypes are created. The recently described Purple Body gene (Bias and Squire 2017a, 2017b, and 2017c) has long been overlooked in research articles and little understood in breeder publications.

genetics