A Discussion of the Pink Moscow (Panda) Phenotype …creation, modification and when needed reconstruction

© Alan S. Bias

Permission granted for nonprofit reproduction or duplication of photos and text with proper credit for learning purposes only.

November 26, 2012

Panda Male (XY^Mw _PkPk) 

Introduction:  As I don’t breed purely by scientific method, nor solely for show and consider myself a stock breeder first and foremost, I’ve been searching for a term or phase to encompass this amalgamation of three distinct schools of thought.  One that describes what guppy breeding means to me and my approach towards it.  Recently, long time Betta breeder and judge, now fellow Swordtail  Guppy breeder, Prof. Leo Buss offered up the following in correspondence:  “Pursuing aesthetic goals in a scientifically informed fashion.”  As this is much more eloquently stated than my abilities allow for, that’s what it shall be.

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…

Breedings:  The first Panda strain I bred in MT was rumored to have been descended from Tsutsui stocks.  It had potential for very long dorsal extension, at least in the world of Panda’s, and periodically produced homozygous blau pink individuals.  In this mutation the dorsal was always clear.  The caudal expressed as clear narrow flag tails with bits of red and translucent blue bodies devoid of other color pigment.  For this reason I assumed it to be what is now commonly referred to as European Blau (Eb), which in my mind put some doubt on the strains origins.  This also suggests the basic Panda phenotype, at least in this strain, was epistatic to red.  Barring was only present in a portion of the males and always partially masked.  I did not attempt to verify if autosomal Z-bar (Ze) or sex-linked Tigrinus (Ti).  One of the few outcrosses I did with this strain involved a Purple Moscow Delta * Panda breeding.  The F1 were sib bred to produce a nice line of Panda with Purple Body Mutation (Pb) with a noticeable reduction of coloration in pectoral fins.

Two years ago I intended to obtain Panda’s and again use the homozygous pink (Pk) females joined to select Purple Moscow (Mw) males as foundation for a new strain.  By doing so would produce a Panda strain for both blue and purple peduncles.  But this would have to wait.  After obtaining, my current Panda strain initially demonstrated poor viability in females which necessitated an outcross.  Subsequent outcross with Panda males as sires seemed to confirm weakness in females.  With no available classes for North American show entry, interest and availability of Panda’s in North America has seriously decreased over the last decade. 

Strain Reconstruction

Generation1:  For initial outcross I set up a breeding group consisting of a grey Panda male with three existing sons to be bred with several Golden (gg), IFGA Bronze Delta, females obtained from breeder Rick Grigsby.  These females were utilized only for initial outcross to produce 1^st generation F1 and discarded shortly thereafter.  All heterozygous Pk males in the F1 were discarded.  I’ll note that all F1 males were traditional dark shouldered Moscow Delta phenotype with a weak snakeskin pattern in the peduncle and dark variegated dorsal / caudal.

R. Grigsby Bronze Delta Females

Generation2:  Resulted from a BC1 backcross, again involving all four original P sires and a select group of 6 F1 females.  In this manner I could reinforce any retained X-link Moscow color traits and also produce 50% Panda.  It had to be considered such a route could reinforce any remaining detrimental X-linked fertility traits I was trying to eliminate.  Heterozygous Pk males and females in the BC1 were discarded.  Only those males and females which expressed homozygous Pk in conjunction with Mw were retained.  Staring with this generation females were selected for increased green iridescence on the topline.

Generation3:  Production of the 3^rd generation left me with a bit of a dilemma.  The 2^nd generation BC1 in theory had recombined the original X’s in 50% of females and 100% of males also possessed the same X.  However, with continued backcross it was possible to lose the autosomal recessive gg.  Not only did I wish to retain this trait into the 3^rd generation, but wished it to express.  For this reason I sib bred the 2^nd generation BC1 offspring, and hoped 1^st generation simple outcrossed had resolved issues with females.

Several 2^nd generation BC1 males were individually set up with 2-3 sibling females each.  Drops were collected from each breeding group to identify which, if any, males and females were heterozygous for gg by production of Golden offspring.  After one male was identified, all other breeding groups and their offspring were discarded.  This decision based on his superior phenotype and as a means to conserve space

2^nd Generation Heterozygous Golden Panda Male (XY^Mw _{PkPk gg})

From this sole breeding group it has been possible to produce strong, hardy and viable Panda with the addition of an autosomal Golden Pink Moscow Variant.  Collection of fry from this group is ongoing to identify any sons which exhibit superior phenotype to their sire.  In effect, an intentional genetic bottleneck for specific intent.

Generation4:   To date most members of this generation result from ((Golden Pink Moscow) * (Golden Pink Moscow)) breedings.  As expected all are gg and will likely be maintained as a distinct line.  Golden guppies are known for less density of coloration in the body and finnage.  Pk still has the same effect on melanophores on scale edge, only now more exaggerated not only in body, but especially finnage combined with gg.  Many grey Panda express partial barring that is near completely masked with maturity.  So far this barring is present in 100% of gg males, but was not expressed by their 2nd generation sire in the photo above .  This would seem to suggest either a X-linked Tigrinus (Ti) or an autosomal dominant version of Zebrinus (Ze).  As males of this phenotype near maturity the barring is still completely visible.  The peduncle has darkened heavily, but retains very iridescent features.

Golden Panda Females (XX _{PkPk gggg})

                               

Immature Golden Panda Males (XY^Mw _{PkPk gggg})

Additional non-Pk females containing genetics for Pb, blond (bb) and albino (aa) have been introduced for production of other Panda variants.  Sib breedings of F1 offspring have commenced.  In each case of outcross utilizing Panda males the expressed Moscow Phenotype in F1 hybrids remains surprisingly consistent:  1. Blue shoulders, 2. Silver snake-skin like peduncle and 3. VAR finnage.  This being nearly identical to the earliest reported Moscow half body snakeskin strains.  Is this indicative of the initial Moscow inputs of the strain or does it include those from introduced females?  I believe it does reveal the three traits to be in “complex” as little if any deviation is visible.  The most visible stems from introduction of yellow color pigment via my Vienna LS females to produce blue-green shoulders, yellow snake pattern and green VAR finnage.   

F1 Hybrid (Panda * Albino Vienna LS)

Discussion:  Pink Moscow as they better known in Europe, are a composite phenotype created by the blending of predominantly Y-linked Moscow (Mw) and homozygous autosomal Pink (Pk) traits.  In a basic grey body form are notated as:  XY^Mw _PkPk  and commonly referred to as Panda’s.  A quick search of images and breeder webpages on the internet will reveal subtle variations between individuals, both male and female in grey form. It will also show variants with additional autosomes.  Are these examples all reflective of the original phenotype documented in Tsutsui’s Panda strain, and for that matter what constitutes a strain?

Generally, a named strain is a very line bred or long-term bred to produce recognizable phenotype.  Individual breeder(s) do so in hopes of a strain which breeds true to itself with a high degree of replication.  It takes line breeding to reinforce many of the subtle traits a strain is known for.  Those that go beyond simple sex linkage or autosomal inheritance resulting in phenotypes from combination and complex.  A hybrid phenotype is just that, it is not a strain.  The IFGA and other show guppy organizations tend to get around this quandary in a rather simple fashion.  They view things almost exclusively based on categorization by visible phenotype as expressed at the moment, and not strain names.  This works rather well for judging purposes, in most situations, and avoids a lot of the pitfalls they may result from differences of opinion on genetics.

Some strains are highly fixed to a single phenotype with little variation and many breeders adhere to this in both practice and philosophy.  Others may be recognized for autosomal variations such as grey, blond (IFGA gold), golden (IFGA bronze), or albino.  They may also reflect variations such as solid or variegated finnage as in snakeskins. Or even short fin or long fin variants.  The list goes on.  Again, many breeders adhere to this more “fluid” definition of a strain in both practice and philosophy, while others do not.  I fall into this latter group of breeders preferring very complex, yet fluid strains that express a host of variation.  The only true precursor is you are breeding for intent.

When breeder intent is to duplicate the original definition and you continue breeding along criteria that will further refine the results to meet that original definition, you are breeding towards a named strain.  To further argue that source genetics must be documented as descending from the original breeder is counterproductive.  Simply do so if you feel a need.  Most guppy phenotypes are readily reconstructed from unrelated sources.  What is important is your understanding of them.  Each of the variants presented either in discussion and/or photographs in this article are genetically Pink Moscow’s.  So to answer the initial question:  Are these examples all reflective of the original phenotype documented in Tsutsui’s Panda strain?  No…  

As a breeder you have the discretion to put your own individual signature on a strain through modification.   I find it best to acknowledge any deviation and resulting variants.  In example, my primary interest in guppy breeding has always been and will likely always be Swordtails.  In specific Vienna Emerald Lower Swordtails.  My strain is comprised of several lines composing many phenotypical traits that result from specific combinations of X, Y or even X & Y-link traits further influenced by several autosomal traits.  These traits may be standalone or they may be in linked complex.  I acknowledge they do not meet the original documented European definition of a Vienna Emerald, for this reason I refer to my swordtails as of “Vienna Type” and not “Vienna Emerald”.  In documenting I normally refer to specific variants by genetic name and notation.  Example:  Asian Blau Vienna Lower Sword Y^{Ls SmIr} X _Ab.

3 month old Golden Pink Moscow Males (XY^Mw PkPk gggg)

As demonstrated in my recent breedings, with a little knowledge of guppy genetics and patience a breeder can often easily reconstruct phenotypes, including the Panda from a single male in as little as two generations.  The inheritance of the Pink trait is no different from many autosomal recessive alleles.  Either sex is capable of passing Pk in unexpressed heterozygous form.  Still it is best to qualify use of the term “unexpressed”, as some visible modifications to melanophores in heterozygotes are visible in both Pk and gg.  Visually Pk shares several similarities with Golden (gg), also known as IFGA Bronze, in relation to melanophores. 

Homozygous Pink Moscow fry, regardless of additional autosomes, are easily distinguished at birth by a highly visible float and eyes which seems to fade with age.  Panda are found to have either black or silver eyes at birth.  With the appearance of secondary coloration from Moscow traits over the eye socket dominant or flashing males take on a nearly pure black eye.  Careful examination of fry under handheld magnification reveals a dark region over the topline extending to and increasing in coverage over the cranial region and above the eyes.  This stems from enhanced manipulation of melanophores in these areas and to a lesser degree in the flanks above the abdominal cavity.  This continues to increase with age and will lesson perceived brightness in regions found at birth.

Grey Panda Females (XX _PkPk)

Just the opposite seems to occur in the lower peduncle, with an increasing reduction from below the dorsal base towards the caudal base.   Further revealing an “opaqueness” of flesh that is found over the entire body in Pk homozygotes.   Again, a similar phenotype found in homozygotes for both Pk and gg phenotypes.  

Without the addition of the Half Black genes Nigrocaudatus (Ni or NiII)  to Pk it is hard to see the gene pink as “color pink”, as it more resembles “white”.  Pink guppies are considered capable of expressing all colors typically found in guppies except red, as a result of the Pk gene.  It should be noted the existence of several Pingu strains w/visible red Mw in the shoulders.  This and the ability of Panda to express Pb in the peduncle  and Homozygous Eb Pink Moscow to express limited red in the peduncle casts some doubt on the theory of homozygous pink completely suppressing expression of red pigment via epistasis.  When Pink is found in combination with the Ni or NiII red color pigment in finnage is modified to a pale orange.  Fixed strains in this combination are often referred to as Pingu.  In some instances it is difficult to tell the difference between this modified orange and unmodified yellow pigment.  Red pigment may result in clear or light dorsals, while yellow can enhance.   

There are nearly as many phenotypical variations in Pk females as males.  This stems from their individual genetic background and how much effort has been put into re-enforcing original X-link Moscow traits of foundation sires.  After outcross, initial homozygous Pk females are often lighter than those from line bred strains.  A “pink” peduncle is still visible in either case, although the body may appear little different from a heavily reticulated non-Pk grey bodied female.  Even in these instances they will change with age as lighter “fleshy opaqueness” is still present, albeit reduced in expression.  Heterozygous gg females express more intense reticulation compared to regular siblings. Homozygous Pk females with a single dose of gg often express a visible difference in scale pattern from simple homozygous Pk siblings.

Grey Bodied Heterozygous Golden Pink Panda Female (XX PkPk gg)

Panda are not a round tail guppy in a traditional sense as a result of genotype.  Caudal shape is a result of homozygous Pink modification through suppression of Pigmentierte Caudalis (Cp), but may be further enhanced  if X &/or Y-link round tail (Rndt) genetics are present.  Most breeders find it wise to select for the darkest caudal and dorsal with clean round shape to avoid either exaggerated clear trailing edges, clear patches, or irregular shape.   

Homozygous Pk Vienna Swordtails -  Photo Courtesy of Björn Lundmark

It is routinely assumed by many breeders that homozygous Pk in conjunction with Mw modifies parental strain finnage (dorsal and caudal).  This assumption is twofold in error; 1.  Extension genetics are not removed, just suppressed to varying degrees by epistasis. 2.  Homozygous Pk in itself is capable of suppressing extension genetics in several strains.  In example above are Homozygous Pk Vienna Swordtails bred by Björn Lundmark.

In recent years I have noted several autosomal homozygotes routinely result in body modifications.   In well-bred Panda strains both males and females exhibit a type of “chunkiness”.  Being defined as; more tightly coupled in both the abdomen and peduncle than either parental stock.  Overall structure of the head and gill plates are also more “rounded” than either parental strain.  Though expression may be enhanced from combination of Mw + PkPk, there is a similar effect found in homozygous AbAb fish.  An autosomal recessive Zebrinus (Ze) in homozygous form has had just the opposite effect in my Vienna LS;  1.  Delaying maturity to produce a “long lanky” body.  2.  Diminishing dominant epistatic effect of Y-link LS over X-link DS to reveal “topspikes.”

Panda Male with X-link yellow pigment (X^YY^Mw _PkPk) showing clear edge on caudal

One of the more noticeable traits in Panda is prevalence for clear trailing edge on caudals.  As dorsals commonly exhibit less of this modification it would be easy to believe the effects of pink are limited to the body and caudal coloration.  Or are they?  Panda caudal and dorsal color is biased towards blue iridophore and melanophore modification.  While the dorsal in a Panda often looks very dark and solid, outcross often reveals Variegation (VAR) to be present.  This is a noticeable deviation from expressions held in common with gg.  Homozygous pink is likely suppressing expression of VAR, while it is commonly expressed in gg.   Depending upon mood dorsals can be very lightly colored in Pink Moscow.  This may result if red pigment is suppressed by Pink or if color is predominantly based on blue iridophores.  Incorporating an X-link for yellow fin coloration can override some of these issues.   

Without any additional color pigment and reduced melanophores Blond Panda often express clear dorsals and are rather flat in body color.  Blond Glass Belly Panda with reduced iridophores even further exacerbate this expression.  While Albino Panda can be similar to blonds in expression, there are marked differences in both iridophore and melanophore expression.  Not so “washed out” comes to mind.  Male and female grey Glass Belly Panda, with higher retention of melanophores, clearly show reduction of iridophores in both the body and finnage.  

Glass Belly Panda (XY^Mw _{PkPk GbGb} ) courtesy of P Shaddock

The overall body color on Panda is a result of blue iridophores in combination with homozygous pink.  It is easily modified to purple with the addition of Pb or green with the addition of yellow pigment.  While a Panda may seem black, closer inspection reveals standalone blue is still visible in select areas on the skull, shoulders, peduncle and caudal base.   Most breeders select for a solid black coverage with attention to degree of iridescence.  A flatter black Panda has been achieved by European breeders, and appears periodically in my stocks, similar to a Black Moscow Delta counterpart.  From available evidence it appears this was accomplished with increased silver iridophores at the expense of blue.

Grey Panda with pronounced silver iridophores

All finnage on a basic Grey Pink Moscow expresses nearly solid black, regardless of additional pigment, though iridophores can bleed heavily into the caudal base.  This includes; dorsal, caudal, pectoral, pelvic, and anal.  Homozygous Pk results in intensified collection of black melanophores in certain regions of the body and fins.  At first glance the addition of homozygous gg to homozygous Pk appears to reduce this effect; Magnification reveals it to be further amplification of collected melanophores in limited regions.

5 month old Golden Pink Moscow Males (XY^Mw PkPk gggg)

One of the more genetically intriguing variants combines both Pingu and Panda phenotypes:  (X^Ni Y^Mw _PkPk).  The anterior still resembles Panda.  There is deviation from Panda phenotype in all finnage.  Not just limited to the typical lighter colored Pingu caudal and dorsal.  It includes the pectoral, anal and ventral fins, which have lost all or most black coloration as the result of Ni.  (Note:  Reasons will be expanded upon further down.)

Pingu Panda (X^Ni Y^Mw _PkPk) courtesy of D Czajkowski

The posterior is classic Pingu peduncle and finnage, though pink stops just short of early versions which extended to dorsal base.  Many Pingu today are similar and exhibit black on the topline in front of the dorsal with a Mw shoulder, likely from Moscow Delta foundation sires.  Original Pingu had two distinct shoulder types.  One was darker in shoulder and topline, but did not possess Mw genotype.  The second was an “Old Fashioned” shoulder pattern in which a red stripe was suppressed via epistatic effect of Pk.  Leaving for the most part only white leucophores or silver iridophores visible (see photo below.) In both cases Pk often extended into the abdomen.

Ca. 1985 Pingu (X^Ni Y _PkPk).  Descendants of David Liebman stocks

 maintained by late Don Sauers and myself

Pink Moscow Variant coloration at the juncture of peduncle  / caudal (not inclusive of all potential)

Conclusions:  Pink Moscow are routinely bred and shown in both Asia and Europe by a dedicated following.     A lack of defined class in North America has restricted both interest and development. In all locations a loose definition of what actually comprises a Panda Guppy has allowed for a diversity of type to arise from a singular phenotype.

Based on the ease of creation it would be safe to ascertain that few if any Pink Moscow found today actually descend from either initial European or Asian (Y. Tsutsui) stocks.  The diversity of phenotype in today’s Panda strains not only is indicative of a variation in foundation Moscow genetics utilized for Y-link traits, but also female genotype.

Many guppy breeders view the Panda phenotype as a simple combination of Moscow blue and homozygous Pink.  This fails to encompass:

1.      Additional autosomes breeders can incorporate to create complex phenotypes very diverse from original descriptions,

2.     Neglects the line breeding needed for refinement into individual Strains,

3.      The diversity of genetic sources used in foundation lines,

4.      Degrees of intensity based on mood of the individual fish,

5.      A non-demanding physical structure.

Basic Panda are fairly similar in genotype.  After initial crossing of parental stock, differences can be readily visible for several generations depending upon breeder selection, compounded by loss or retention of any X-link Moscow traits.  There is clear evidence of manipulation of black melanophores at birth in Pink Moscow’s. 

As with most guppy strains a clear progression of secondary color / pattern development commences at onset of sexual maturity.  Increased iridophores to reveal silver / blue and expression of barring; followed by appearance of color pigment; and finally, in contrast to cellular layering, further enhancement of black melanophores to partially overshadow iridophores.  Suggesting some black in Panda’s is ectopic in nature and not limited to lower cellular levels.

Panda Moscow Lower Sword (LS + Mw + Pk + Ssb),

Photo courtesy of breeder Olof “Ollie” Boberg

In all but a few Pink Moscow strains coloration is highly motile in nature as a result of Mw gene(s) interaction between black melanophores in conjunction with structural iridophores & color pigment.  When possible it is wise to delay selection of your breeders to identify those with best density / intensity of coverage in body and fins.  As a result of foundation Moscow Blue (blue iridophore) genotype, descendants of Tsutsui Panda stocks were very dark colored in the peduncle.  There may have been a blau component (Eb or Ab) which was not documented.  Today, depending upon breeding Panda are also found in both green and purple body mutation (Pb).  This could stem from use of Pb females or Purple Moscow males as parental stock instead of Blue Moscow.  

Observation reveals to breeders how zones of regulation are allowing for the varied appearance in today’s Panda.  Easily evident are increased melanophores in topline and finnage, iridophore / pigment modifications anterior and posterior.  Less noticeable at first glance are zonal effects on patterns such as Zebrinus / Tigrinus and Snakeskin.  Normally found over the entire peduncle, like many other strains, they can be restricted to either upper or lower quadrants in Pink Moscow.  In the males below barring is present in both upper and lower, while snakeskin is restricted to the upper.  I have not witnessed the latter in inverse, snake in the lower, as is possible with other traits such as Saddleback (Ht).

                     

(Left photo) Panda Moscow w/barring in upper
 & lower peduncle. Snakeskin in the upper peduncle. 

(Right photo) Blond Vienna LS w/barring

 in upper peduncle quadrant 

Homozygous Pink has often been characterized as having its greatest effect on iridophores.  However, this is not necessarily the case.  Pk exerts a far reaching impact on all levels of cellular structure in regards to color and pattern.  Most breeders acknowledge guppy color cell layering to consist of:  A lower layer of melanophores (black); a middle layer of leucophores/iridophores (minimally being blue / silver / white); a top layer of zantho/erythrophores (yellow / red).

In Goodrich, et al., (1944) regulation of phenotypic expression of melanophores by autosomals Blond and Golden are studied.  He describes Wild-type as “in some respects intermediate between the Golden and Blond.”  His  research divulges several types of melanophores:  1.  Dendritic (on the scales), 2.  Corolla and Punctate (on the body).  For the most part they are present prebirth, at birth or shortly after birth.  While Wild-type and gg guppies have the largest dendritic melanophores, bb has the smallest. Yet wild-type and bb have nearly the same amount (concentration) per square mm of tissue sample.  

Goodrich, et al., (1944)

In Nayudu, et al., (1979 No. 2) melanophores in Wild-type and three other sex-linked traits are studied.  Of particular interest in relation to Pk are her results for Half Black (NiII).  She defines them as “mutant”, being ectopic and larger than normal.  The mutant melanophores of NiII, Flavus (Fla) and Cp are present in at least the posterior peduncle region, caudal / peduncle juncture and dorsal base.

Nayudu, et al., (1979 No. 2)

Autosomals blond and golden are both considered epistatic to black in homozygous form.  Not by directly affecting melanin synthesis, but by regulating melanophore size.  Blond has little or no effect on Half Black (NiII), which has been shown to consist of larger sex-linked mutant black melanophores.  In contrast autosomal Pink aggregates concentration of regular melanophores and suppresses mutant melanophores, based on Panda and Pingu phenotypes.  Thus, being in divergence from gg and bb, Pk appears to regulate in both instances…  

Pink Moscow Male – top  (XY^Mw PkPk)

 Golden Pink Moscow Male - center (XY^Mw PkPk gggg)

 Het. Golden Pink Moscow female  - bottom (XX PkPk gg)

I used to worry that this wonderful little phenotype would disappear from the scene like so many others have in the past.  Yet, the simplicity of genotype allows for quick reconstruction from many sources.  While the more obvious phenotypes have already been produced in multiple locals, it’s hard to tell what may be presented by breeders in the future.

On a last note, it should be mentioned that Panda Moscow are a notoriously slow growing, but long lived strain.  After a quick growth spurt the first month it takes considerable time to reach mature size and coloration.  If you have an exceptional bodied male in with a group of siblings that just never seems to color up to expectations, remove him to another setting.  Often this is all it takes to reveal the full potential as a result of the motile nature of color found in Pink Moscow.

The final words in this article belong not to myself, but the individual who bred, named and documented the Panda strain.  In his words:  My answer may be abstract Japanese way... I first draw the exact image in my mind the guppy I want to create, then print it in my mind. Then keep thinking of the image everyday when I feed my fish. After a while, fish start to lead me on what to do and my eyes become more keen, so often find the guppies I need from my fishroom without adopting guppies from somewhere else.  This is what I call "Guppy Alchemy." ~ Yoshiki Tsutsui ca. 2005

References:

1.      Robert Gall, (2005), Guppy Labs e-Bulletin, Base Body Color Pink, Volume 7, (July 2005), http://guppylabs.info/july2005/robert.htm (no longer active site - wayback machine capture 2012)

2.      Telephone Interview by Tomoko Young, (2005), A convsersation with Yoskiki Tsutsui, Guppy Labs e-Bulletin, Volume 5, (January 2005), http://guppylabs.info/january2005/YoshikiTsutsui.htm (no longer active - wayback machine capture 2012)

3.      Shaddock, Phillip (2010).  Guppy Color Strains.  Printed in Canada, Pocket Cine Books. [General Reference; Moscows pgs.:  15-36 / Pinks and Pingus pgs.:  113-120]

4.      Heike Savelsbergh, Guppyheike (webpage),  Moskauer Rundschwanz, http://www.guppyheike.de/guppys/pink-mosi-rs/  (10.31.12 active)

5.      Winge, O., Genetic Laboratory of the Royal Veterinary and Agricultural College, Copenhaen  (1927).  "THE LOCATION OF EIGTHEEN GENES IN LEBISTES RETICULATUS" [gene tables and descriptions]

6.      Petrescu-Mag I. V., et al., (2007(, Interallelic interaction between the autosomal Blond and the sex-linked Nigrocaudatus gene in the guppy (Poecilia reticulata). AIR 2(1).

7.      Kirpichnikov, V. translated by G.G. Gause., 1981, Genetic Bases of Fish Selection.  Berlin / NY, Springer Verlag (1981) [gene tables and descriptions]

8.      Shaddock P.,(2008), Blond: a regulatory gene in the guppy (Poecilia reticulata Peters 1859). AACL Bioflux.  1(2):161-164.  Printed version: ISSN 1844-8143

9.      Nayudu P.L., et al., (1979 No. 1), Genetic Studies of Melanic Color Patterns and Atypical Sex Determination in the Guppy, Poecilia reticulata, Copeia 1979, pp. 230-231,

10.  Nayudu P.L., et al., (1979 No. 2), Cytological Aspects and Differential Response to Melatonin of Melanophore Based Color Mutants in the Guppy, Poecilia reticulata, Copeia 1979, pp. 240-242.

11.  Goodrich H. B., et al., (1944), The cellular expression and genetics of two new genes in Lebistes reticulatus. Genetics 29(6):584–592.

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Breeders of many fish species are intent on maintenance and preservation of what already exists.  Guppies present a unique set of challenges if only by diversity of genotype.  As breeders it is easy to believe we can add to the equation while forcing them into a specific mold.     An old adage in the pedigree livestock world states, “You start with a 100% package and you end with a 100% package.”

 All we can do as breeders is re-shuffle the deck for gains in one area and corresponding losses in another.  This is a constant when breeding any species.  There is no way around it.  Seek a balance in your efforts in conjunction with your goals to reveal what Mother Nature will allow within your particular environment…

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