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.


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The intent of this paper is multifold; 1. To identify phenotypic and 38 microscopic characteristics of newly described Purple Body trait (Fig 1 and   39 2). 2. Provide photographic and microscopic exhibits of Purple Body and

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The motile nature of melanosomes in ectopic melanophores may allow for 146 changes in reflective qualities or hue of individuals. In conjunction with 147 zygosity dependent removal of xantho-erythrophores, this may satisfy both 148 female sexual selective preferences for conspicuous pattern of "bright 149 orange" under specific lighting, and maintain crypsis in others (Endler 1978). 150 While frequent evidence of dendritic and/or motile yellow color pigment 151 (xanthophore) structures was detected in this study, none was found for circuli and annulus rings of the scales (Fig 5A and Fig 5B). Reduced, as a 174 result of Pb modification was the expected minimal number of xanthophores 175 that had been found in non-Pb samples. Erythrophores were not reliably 176 detected in scales of near "wild-type" or feral populations in their study 177 (Phang 1985). These cell types combine to produce not only background 178 body coloration, but also increased reflectivity.  and finer in appearance (Fig 7-8). Dendrites are linked together in "chain- The following examples of early coloration in non-Pb and Pb show male 237 expression of violet-blue iridophores macroscopically (Fig 11) and in 100x 238 and 400x (Fig 12-15 in similar fashion (Fig 13-15), as opposed to later mature coloration in 247 which violet and blue iridophores are arranged together in "joined 248 alternating color" groupings in dissimilar fashion. This shows that coloration 249 is nearly complete, while migration to their final location is not. Second, 250 melanophore shape is predominately corolla or punctate in early coloration 251 (Fig 12-14), as opposed to mature coloration in which dendrites dominate.  for mature individuals, reveal that dendrite structure is extremely extended 290 and finer in appearance (Fig 19-20 numbers and punctate melanophores nearly absent (Fig 19). homozygous condition removes red color pigment (Fig 22A-B).  (Fig 31-49). Collected and clustered xanthophore populations 469 were reduced in heterozygous Pb condition and removed in homozygous Pb 470 condition, as seen macroscopically (Fig 31, 36, 41 and 44) and 471 microscopically (Fig 32-35, 37-40, 42-43 and 45-49). The retention of 472 isolated xanthophores, found in all parts of the body and fins in "wild-type", 473 remained intact in heterozygous and homozygous Pb condition. As 474 previously noted, Pb in itself has little or no effect on erythrophore 475 populations.

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Within the rear peduncle orange spot and surrounding edges a

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Macroscopic qualities of non-Pb study male (Fig 50). Melanophore, 628 xanthophore and violet-blue iridophore were found adhering to the spinal 629 column and ribs (Fig 51A-B). No evidence of subcutaneous erythrophores 630 was detected below the dermis, though suspected in micro-dissected the 631 xanthophore cluster (Fig 52); all "red coloration" identified as blood cells. The violet-blue iridophore chromatophore unit (Fig 2A-  air dried for minimal time periods of less than one hour for aid in dissection.

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All samples and images from right side of body, unless otherwise noted.

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No cover glass was utilized, to reduce damage to chromatophore shape,