Color Cell

The guppy has the major classes of chromatophores found in teleosts: xantho-erythrophores, iridophores and melanophores. These color cells render the adult body essentially opaque. A transparent guppy was developed, the See-thru guppy, combining alleles that genetically remove the major classes of guppy color cells: xantho-erythrophores, iridophores, melanophores and leucophores. The See-thru guppy may have interesting applications for scientists already using the guppy as a model organism. In our own research into the inheritance of color patterns in the guppy, the See-thru guppy may be useful for exploring the specificity of mutations to color cell types.

Abstract.  The selection for genes in Domestic Guppies has long been heavily based on sex-linked genes.  In particular Y-linked for pattern and X-linked for color.  Over the last several decades a larger percentage of strains and phenotypes (especially those created by Asian and European breeders) have been produced based on autosomal genes or co-expression of sex-linked and autosomal genes.  The attempt of this presentation is to help breeders gain not only an understanding of autosomal genes, but their interactions in combination(s) and with other genes.  The development of domestic genes, unlike wild counterparts subject to predation, is only hindered by breeder selection and retention.  Results based on 45 years breeding experience of which nearly thirty (30) years have been devoted to strains collectively known as “Swordtail Guppies”, efforts of other professional breeders, and that of the scientific community are presented.

Likely one of the least appreciated guppy phenotypes to be found is Homozygous Asian Blau (Ab).  Such fish  are normally considered weak by-products of popular delta breedings involving blue iridophores and red color pigment;  Blue Topaz, Blue Grass, Half Black (HB) Neon quickly come to mind as examples.  Each strain is created by the removal of red color pigment, frequently an X-link, from phenotype.  It is still contained in genotype, only masked via epistasis.

It is generally accepted the basic Pink Moscow (Pk + Mw) or Panda phenotype arose in several locations to include Europe and Asia.  The late Japanese breeder Yoshiki Tsutsui is generally credited for the first documentation and stabilization into a recognizable strain, which he named “Panda.”  The following is not intended to be all encompassing, and will focus on color / pattern variants and not those involving finnage:  long fin variants.  It is based for the most part on personal experience and observations of other breeder’s results.  To a lesser degree incorporates prior publications, of which I found to be minimal.  My breeding experience and fascination with Panda’s goes back more than a decade.  In the world of delta guppies this hardy, fertile and long-lived phenotype often gets little more than a second glance.  Yet, for these same reasons it maintains a dedicated international following with guppy breeders who also enjoy active strains…

A comprehensive investigation in guppy color biology, pattern formation and a unique hypothesis about the biological basis for guppy polymorphism. Includes chapters reviewing relevant animal pattern research. Includes information about the author's experiments using classical forward genetics.

Animal breeding hobbyists have been useful to science because they identify and isolate color coat mutations that geneticists can in turn use in their studies of the development and differentiation of color cells. This paper discusses a very interesting color mutant, the Japanese Galaxy, tracing its creation from back to a self-educated genetics hobbyist, Hoskiki Tsutsui. The paper discusses a constituent gene previously studied by Dr. Violet Phang, the snakeskin gene (the linked body and fin genes Ssb and Sst). And it discusses a gene previously unknown to science, the Schimmelpfennig Platinum gene (Sc). Through crossing experiments, the author determines that the combination of these two genes produces an intermediate phenotype, the Medusa. Incorporating the Grass (Gr, another gene unknown to science) gene into the Medusa through a crossover produces the Galaxy phenotype. Microscope studies of the snakeskin pattern in Galaxies and snakeskins reveals some parallels with similar studies made of the Zebrafish Danio.