Guppy

PREFACE
Too successfully breed a strain of guppies’ long-term one must first set attainable goals.  After aesthetic value, manipulating a small snapshot of genetics, consisting of fixed strains, has always been my primary interest in breeding guppies.  It is often accomplished by an intense quest into understanding Population Genetics in conjunction with a study of Color.  This article will attempt to expand on my last and focus on potential routes to achieve fishroom goals through two linebreeding techniques.

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.

PREFACE
The intent of this article is to point out how considerations beyond color, pattern and caudal shape play an important role in creating healthy & viable strains.  As such specific references to color study are not made.  They are better covered in publication of study geared to these criteria.

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, ombining 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 atterns in the guppy, the See-thru guppy may be useful for exploring the specificity of mutations to color cell types.

Abstract.  The source of genetic inputs in modern Domestic Guppy strains has long been a controversial topic in breeder circles.  Assumed by many to consist solely of Poecilia reticulata, and considered by others to have multiple inputs from closely related variant populations.  The attempt of this paper is to demonstrate that sum genotype, in particular for at least one identifiable trait known as Iridescens (Ir), stems from an amalgamation through interbreeding of native Guppy populations in divergent stages of incipient speciation; that are capable of interbreeding and surviving in either habitat, and are therefore non-cryptic.  Offspring should not be viewed as interspecific hybrids (between different species in the same genus), as they are capable of viable reproduction, lacking any high degree of decrease in reproductive viability.  Domestic strains, like wild counterparts in reproductive isolation are not speciated.  Results are 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. 

Key Words: Swordtail Guppy, Domestic Strains, Vienna Emerald, Wild-type, Guppy Populations, Reflective Qualities, Smaragd-Iridescens, Iridescence, Poecilia reticulata, Poecilia obscura, Poecilia Wingei, Cumana’ Guppy, Campoma Guppy, Endler’s Livebearer.

Introduction:
When a new strain of guppies or a variation upon one makes an appearance it can seem natural to credit its existence on newly discovered genetics.  Occasionally this is the case.  More often than not after careful test breeding and analysis the truth is revealed to be new combinations of already identified genes.

Although fish have been kept for more than three centuries as ornamentals, and the development of manufactured feed since 50 years ago has contributed to the tremendous growth of this hobby, nutrition of ornamental fish is based on extrapolation of results derived from food fishes under intensive farming conditions. Some research on nutrient (protein, minerals) requirements of growing freshwater ornamental species (live-bearers) in a production environment has been conducted, mainly in Singapore, with emphasis on the provision of live feed during the early stages of the life cycle. Protein requirements varied from around 30% dietary protein for growing omnivorous goldfish (Carassius auratus) to 50% for the carnivorous discus (Symphysodon aequifasciata). Whereas mineral (phosphorus, iron, magnesium, zinc) requirements have received some attention in the guppy (Poecilia reticulata), few researches have concentrated on vitamin requirements of ornamental species. Requirements for fatty acids have been conducted mainly on marine ornamentals (damselfish, seahorses), and accentuated the need for dietary supplementation of n-3 highly unsaturated fatty acids. Fish kept in public and home aquaria presents the problem of diversity of species in the same enclosure, each with its own specific requirements and needs. Maintenance energy levels of ornamental fish varied from 0.068 kJ per day for small neon tetras (Paracheirodon innesi) to 0.51 kJ per day for moonlight gouramis (Trichogaster microlepsis) kept at a water temperature of 26 °C. Research on nutrient requirements of ornamental fish urges for suitable measurements other than only growth rate in order to determine optimal dietary inclusion levels.Les exigences alimentaires des poissons d'ornementation. Les exigences alimentaires des poissons d'ornementation. L'élevage de poissons ornementaux effectué pendant plus de trois siècles et le développement de la manufacture d'aliment depuis 50 ans ont contribué à l'essor de ce loisir, mais la nutrition des poissons ornementaux se fonde sur une extrapolation de données dérivées de poissons de consommation et en conditions de culture intensive. Quelques études ont été faites sur les besoins alimentaires (en protéines, en éléments minéraux) d'espèces ornementales d'eau douce (des poissons vivipares) dans le cadre de production, à Singapour en particulier, et sur la nécessité d'aliment vivant dans les premiers stades de leur cycle de vie. Les besoins protéiniques varient de 30 % de protéine brute pour le poisson rouge omnivore (Carassius auratus), jusqu'à 50 % pour le discus carnivore (Symphysodon aequifasciata). Les besoins en minéraux (phosphore, fer, magnésium et zinc) ont été étudiés pour le guppy (Poecilia reticulata), mais peu d'investigations ont été faites pour connaître les besoins vitaminiques des espèces ornementales. Les besoins en acides gras ont été étudiés chez les poissons ornementaux marins (demoiselles, hippocampes) et se limitent à la supplémentation diététique en acides gras très insaturés n-3. Que les poissons soient présentés en aquariums publics ou cultivés en aquariums personnels, un problème de diversité d'espèces se pose dans un même bassin ; chaque espèce ayant ses exigences spécifiques. Leur besoin énergétique d'entretien varie de 0,07 kJ/jour pour les petits néons-tétras (Paracheirodon innesi) jusqu'à 0,51 kJ/jour pour les gouramis serpents (Trichogaster microlepsis), élevés dans une eau à 26 °C. Dans la recherche sur les besoins alimentaires des poissons ornementaux, il faut utiliser des paramètres adéquats, autres que le taux de croissance pour obtenir les taux optimaux des nutriments.

Introduction:
It seems most new strains come about from one of four scenarios:  1. Random hybridization. 2. Mutation.  3. Crossover.  4. Planned modification.  The latter should stem from a predetermined breed plan with well set goals working with a recognizable parental strain(s) and any additional genotype you wish to infuse.  In such instance one of the first questions that comes to mind is just how much modification is needed for distinction as a new strain from it's parent?  When is it a new strain and when it is just a variant of the parental phenotype?

Genetic linkage maps of the guppy (Poecilia reticulata) were constructed from independent crosses between the Tuxedo strain and a feral line (Wildtype). Segregation patterns of random amplified polymorphic DNA (RAPD) markers and phenotypic markers were investigated in F2 offspring of Tuxedo ♂♂ × Wildtype ♀♀ and Wildtype ♂♂ × Tuxedo ♀♀ crosses. Among the 300 and 276 RAPD markers scored for the respective crosses, linkages were identified for 230 and 212, respectively. The Tuxedo ♂♂ × Wildtype ♀♀ and Wildtype ♂♂ × Tuxedo ♀♀ maps spanned 2100 Kosambi centiMorgans (cMK) and 1900 cMK, respectively, in 28 linkage groups. Average marker resolution was 10 cMK. Genome length was estimated at 4410 cMK and 4060 cMK for the respective crosses, with an average physical distance of 166 kbp/cMK. Several RAPD markers were closely linked to or mapped onto the loci for the sex-determining region (SdR), and the sex-linked black caudal-peduncle (Bcp) and red tail (Rdt) genes. These primary linkage maps are the initial step toward the construction of a composite high-density map to facilitate map-based cloning and marker-assisted selection of quantitative trait loci that are essential for the development of comprehensive breeding programs for the guppy.

In the year 1937 A. E. Robson of High Gate, London, England introduced to United Kingdom (UK) members of the Guppy Breeder's Society (GBS) a new strain which would become known among Domestic Guppy breeders as the "Robson Guppy".  A strain produces a visible phenotype; a grouping of multiple traits.  The Robson strain incorporated two unique traits in females at the time.  First, the phenotypical structure of the dorsal resembled that of males from other early strains, still bred today, including the Speartail.  While the caudal structure resembled that of the Roundtail, also still bred today.  The primary noted difference  with Roundtail being a long tapering dorsal with extension well into the caudal round, as compared to early and modern Roundtail's which possess a much shorter and rectangular dorsal that does not extend into the caudal round.

In response to both of these theories, I state each as being only partially correct.  I propose: That Metal Gold (Mg), Stoerzbach (s), Snakeskin Body (Ssb) all in homozygous state, and a “missing trait” are required to produce the original metallic Micariff phenotype in full body expression.  That this missing trait is required in conjunction with Steorzbach a "full body" trait acting as a precursor to effect the "metallic gold Micariff phenotype" (hereafter metallic) in both body and finnage.  As a result two actual expressions are commonly produced when Stoerzbach is lacking or in heterozygous form;  metallic and non-metallic body (hereafter non-metallic).

At some point in time many serious Domestic Guppy breeders are faced with a similar situation presented in the title of this article. No, I'm not talking about the two often asked questions leading to tank creep; "do I have too many strains or not enough tanks?"  Yet if you can satisfactorily answer the question for yourself in regards to what follows, the answer may lend a hand in solving both of the prior questions for you as a breeder.  In turn it can strengthen your breeding program and help achieve desired results.  To start you must first have a definition of what is a breeding strain and what is a breeding line within your strain.

Genetic variability within and among feral populations and cultured strains of the guppy (Poecilia reticulata) was investigated by random amplification of polymorphic DNA (RAPD) fingerprinting. Feral guppies were collected from 6 isolated populations (BT, Bukit Timah; NS, Nee Soon; TS, Tuas; MF, Mount Faber; KR, Kranji; LI, laboratory-inbred feral line), while the Tuxedo and Green Variegated strains were sampled from 2 guppy farms in Singapore. Pairwise genetic distances analyzed by unweighted pair-group method with arithmetic means revealed distinct clustering of guppy individuals into their respective populations and strains. Percentage polymorphic loci ranged from 54.96% (TS) to 68.70% (KR), while average heterozygosity ranged from 0.220 (GV) to 0.271 (KR). In contrast, TS guppies had the highest (0.850) intrapopulation genetic similarity (S), whereas KR had the lowest (0.781). Among populations and strains, S ranged from 0.703 (between GV and LI) to 0.809 (between NS and MB). The GV strain S was closer to TX (0.784) than to the feral guppies. Bootstrapped genetic distance trees depicted 3 major nodes comprising BT-TS, NS-MF, and TX-GV. Principal coordinate analysis also differentiated the 6 feral populations from the 2 cultured strains.

Studying the mechanisms by which immature males learn courtship behaviour is essential to our understanding of the evolution of different mating strategies, yet generally this has been neglected. Here I demonstrate an effect of early social experience on the sexual behaviour of male guppies, Poecilia reticulata. I tested whether the social rearing environment (visual access to females only, males only or both males and females) affects males' sexual performance, including the time and frequency of courtship displays and forced copulation attempt frequency. I conducted trials in which focal male guppies were allowed to interact with a female. Males that experienced early social interactions with mature males performed significantly longer courtship displays than males that grew up without observing other males. This result suggests that young males learn to court efficiently by observing other males courting. Males raised with females performed more forced copulation attempts, possibly because males might need to physically interact with females in order to learn to strategically alternate courtship displays and forced copulation attempts. Early social interactions may play a stronger role in the structure of the mating system in guppies than previously recognized, and might contribute to the differences in sexual behaviour observed between different populations of guppies.

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.

Nestled high in the Jemez Mountains of Sandoval County, New Mexico, at an elevation of around 7350’ (2240.28 meters) reside one of the most unique and oldest established feral populations of Poecilia reticulata in North America.  This self-sustaining population is not only a jewel for livebearer enthusiast tanks, but the focus of much formally published research.  As with most thermal spring environments throughout the United States, conditions can be rather harsh for a species evolved in a tropical setting.  Overall, size of habitable range is normally limited by temperature extremes, predation, and water chemistry to the first few pools near issuing thermal source.  In others habitation will extend downstream to a point where minimum survivable temperatures are no longer maintained during winter extremes.

In some mating systems males should benefit from mating with virgin females because of their higher reproductive value. We determined experimentally whether and how males distinguish between virgin and recently mated females in the guppy, Poecilia reticulata, a promiscuous livebearer. In a free-swimming experiment, males showed flexible mating behaviour by adjusting their tactics according to the mating status of the female they encountered, virgin or mated. Males followed, nipped and copulated with virgins more than with mated females, but they performed more sneaky copulations with mated females, possibly because the latter were more reluctant to mate than virgin females. When, in another set of experiments, males received only the visual cues of both virgins and mated females they showed no preference for either, but when they were exposed only to the female olfactory cues, they associated considerably more with the smell of virgin females. These results suggest that male guppies assess female behavioural and olfactory cues to determine female virginity and then use different mating tactics depending on the female's status. It is possible that the changes in male mating behaviour increase male reproductive success.

Keywords

alternative mating strategies;
female mating status;
female reproductive status;
guppy;
male mate choice;
Poecilia reticulata;
sexual selection

This is one of those topics that generates very little documentation in the hobbyist world.  In the scientific community it is just the opposite and a number of comprehensive studies have resulted in excellent publications.  What is not so easily gauged and often overlooked is the effect of Hemiray Bifurcation in a Swordtail strain.  The weaknesses it creates and how you should base breeder selections.  As Swordtail Guppy breeders, we deal primarily with male finnage as clear &/or roundtail is the norm for females in all but a few strains.  From the start we are at a distinct disadvantage vs. broad tail breeders.  The simple reason being mother-nature goes against us at every chance.  Bifurcation alone creates an ever broadening of the caudal.  We start with naturally occurring tail extensions that are very small, thin & short.  These having evolved over countless generations with well defined characteristics into rigid gene complexes.  Then we attempt to force not only  lengthening, but thickening in the process.  In the end retain a distinct point while encompassing an increased number of colored hemirays at maturity.

When it comes to collecting feral populations of Poecilia reticulata in North America, West Virginia is not one of the first places that come to mind. While many Guppy enthusiasts are aware of Florida feral ditch populations derived commercial farm escapees, few realize that self-sustaining populations exist in thermal spring environments throughout the United States.  Conditions in each of these thermal locations can be rather harsh for a species evolved in a tropical setting.  Overall, size of habitable range is normally limited by temperature extremes, predation, and water chemistry.