Asian Blau Japan Blue Swordtails

Asian Blau Japan Blue Swordtails

© Alan S. Bias

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

April 9, 2012

Mixed tank of pure JB and  JB * Vienna outcross with X-link yellow

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.

A year and a half ago I once again gave in to the appeal of Japan Blue (JB) and a chance to work with this alluring phenotype.  My first hands on experience with JB came back in 2004.  I started with a typical grey wild-type strain with a clear roundtail lacking extension or caudal color.  Combined with females from an X-link Lace Snakeskin Double Sword strain it was easy to produce, and then fix a nice line of Variegated (Var) JB Double Swords after 2-3 generations.

  Variegated (Var) JB Double Swords

Over the last couple years a line of Japan Blue Swordtails has been making the rounds on Aquabid.  Inquiries with several sellers as to origins were met with the same vague responses that hinted to importation from Asian Breeders.  What drew me to this strain were two particular traits:  1. First and foremost they were swordtails to varying degrees.  2.  Second intense iridescence and what appeared to be more than normal blue coloration into the anterior portion of the body.

Discussion:  

Accepted theory states that JB was initially identified as a Y-link mutation found in a feral population of wild-type guppies in Japan.  Infrequent crossover to X-link has since been identified in a few strains.  Blue patterns in guppies is not limited to expression as a result of JB.  Recently, in Venezuela, French breeder Frederic Nicole collected a stunning new blue phenotype in a population of Endlers Livebearer.  Blue covers the upper quadrant along the entire length of the peduncle and then some.  It seems to have more in common with Lazuli than Japan Blue.  In my fishroom there has been only one suspected instance of X-link JB in the last 10 years.  Interestingly, the incident involved ½ a dozen males in a single drop of about 12 males in total from a Schimmelpennig Platinum Double Sword * Lace Snakeskin Top Sword breeding, and not an isolate individual.   I had culled the dam prior to sons coloring up and worse failed to capitalize on the potentially X-linked JB type pattern for lack of tank space at the time, or so I decided.  This was a very poor decision in hindsight.

X-Link Japan Blue type pattern

In any JB strain the pattern is almost exclusively ½ body with a clear line of demarcation starting just below the base of the dorsal fin, or slightly before, and running the length of the peduncle.  The exact location often seems relevant to the level of improvement found in a strain.  There also seems to be a direct correlation between Emerald Green Iridescence (EGI) determining how much the pattern bleeds into the caudal.     

Other factors can influence the intensity and shade of blue coloration found in a Japan Blue male.  The addition of yellow pigment in the body from genes such as vitellinus (vi) can modify appearance from blue to green or even yellow.  The addition of red pigment can dilute from blue to lavender.  

 Blond JB * Vienna Lower with X-Link yellow and metal

Based in part on these facts the perceived increase in blue coloration into the anterior portion of the body in this JB strain should result from additional additive effect or other genes.  Not the JB itself. 

Test Breedings:

In brief email correspondence I requested only males exhibiting a very long lower sword and if possible dorsal color of any type.  The seller obliged on the first request, but was unable to provide any males with dorsal color as the strain did not have any.    My initial approach would be several generations of sib breeding to identify existing traits in pure form.  This revealed a percentage of males expressing “blue lips”.  Colored lips are often found in metal / platinum strains.  These males also tend to express the most intense blue and increased level of coverage.  Males exhibiting a lower sword would generally pass the trait to sons to varying degrees in shape and length.

Japan Blue male with hyaline dorsal

In multiple purebred litters over 3 generations a portion of males would posses lower swords and a portion fairly mismatched double swords.  The reminder being clear roundtails.  This indicated not all the JB females were homozygous for producing or enhancing sword shape.  Many of the roundtails and lower swords also showed oculatus (oc) spotting.   Sib breeding also produced about 25% males with a red shoulder stripe.  The presence of Zebrinus Bar (Ze) was evident as secondary sex link colors started to manifest in young males.  This was quickly covered over as JB made its appearance.  At the time, while suspecting it to be autosomal dominant Zebrinus Bar (Ze), I could not rule out autosomal recessive Tigrinus (Ti).

Autosomal Zebrinus Bar, as later identified

Less than 1 in 10 males would exhibit some patchy black dorsal color.  Purebred sib breeding also told me the hyaline (clear) dorsal resulted from a lack of X-link dorsal color or it was epistatic to any existing genes for dorsal color.  Therefore, likely near impossible to eliminate without outcross.  Hence, making an outcross with my Vienna lowers a logical choice as they posses both Y and X-link for yellow pigment and gold iridophores in caudal / dorsal and to some degree.  At this point I discontinued pure breeding the strain with better lower males resembling the individual below.

 Asian Blau Japan Blue Lower Sword with hyaline dorsal

Reciprocal outcrosses to my Line 1Vienna Lower lines helped substantiate several developing theories about this JB strain.  It showed JB females were actually contributing not only to caudal fin length, but the overall shape itself.  Results hinted at fin extension being mostly X-link for swords, regardless of type.  Notice that I say extension and not the sword itself.  Sib breeding of F1 Vienna Lower * JB revealed in the F2 and F3 via recombination, that the foundation JB females often only carried extension on a single X-link or non at all.  I note that not a single incidence of bar has occurred in my Line 1 Vienna Lowers in over a decade, though I breed for it regularly in my Line 2.  Reciprocal crosses between JB and Line 1Vienna Lower showed the barring to be autosomal dominant Ze as it appeared in both directions of F1 offspring.  So this should eliminate further consideration of Ti as the source of barring.

Lacking tanks space for breeding the double swords I have culled them for the most part.  While I have done a few test breedings to evaluate, outcross with Vienna Lower females and recombination in the F2 / F3 hinted at two forms of doubles.  The best matched possibly resulting from a single X-link and another resulting from a combination of X-link top sword and X or Y-link lower sword.  The latter version likely in complex as no pure Top Swords have ever presented.

Segregation and recombination in F2 / F3 crosses (from both reciprocal crosses) in addition to F1 * Vienna backcross (BC) revealed two concerns.  First and foremost the JB Y-link lower sword does not appear completely dominant to either type of double sword or recurring clear roundtails, though the latter phenotype has been reduced in occurrence.  I would not be surprised if better defined test breedings of doubles found them to be epistatic to lowers as is common with Vienna Swordtails.  Second, optimal lower sword shape is not exclusively controlled by Y-link alone.  Suggesting JB X-links &/or autosomal input for sword shape and length.

The continued use of Line 1 Vienna lower females for BC creates an issue all to itself.  It produces JB males that are a definite shade of Apple Green or a blue with distinct regions of yellow pigment or gold iridophores.

 F1 Grey JB * Vienna Lower with X-Link yellow influence

Two of the first traits I wished to test for / rule out were Stoerzbach and Lazuli.  I see no evidence of Stoerzbach to date.    While I rule out Lazuli as unlikely, I do see similarities to this trait;  1.  Blue coloration in the upper shoulders of some males.  2.  Variation in shades of blue on individual males in distinct regions.

Reciprocal outcrossing to my Line 1 Vienna Lowers has revealed the true secret to this strain.  This being the presence of autosomal Asian Blau (Ab), which is partially dominant.  It not only helps add to the additional anterior color, but the overall color itself.

            I.    Abab (heterozygous) Asian Blau

            II.   AbAb (homozygous) Asian Blau

            III.  abab (non Asian Blau)

I.  Unlike European Blau (Eb), Abab heterozygotes can express yellow pigment and possibly gold iridophores in body and finnage when the genes are present. 

 Asian Blau Japan Blue with X-link yellow

II.  AbAb homozygotes remove / inhibit red pigment to reveal silver (or white) or blue depending upon the type of irridophore lying beneath the color pigment.  As Japan Blue is a mutation of blue irridophores it seems there should be little or no silver in the peduncle.  As seen below in grey form, AbAb fish appear blue/grey and in blond double recessive white.  Epistasis likely prevents formation of swords and colors are limited to blue iridophores, possibly a theoretical gold as evidenced by the presence of green in the body.  

Homozygous Asian Blau Japan Blue (Grey on left & Blond on right)

III.  abab Japan Blue males (those lacking the Asian Blau gene) may show a red stripe on the shoulders or caudal outside the region of influence in traditional JB.

Japan Blue lacking Asian Blau

Reciprocal crosses with Vienna Lower * Abab JB females show they also pass extension genetics to the F1 males.  With selection this enhancement has been easily retained to a high degree in F2 and F3 sib-breedings.  Having worked with Y-link lower swords for many years I am of the opinion that the best length and shape is only possible in combination with the additive effect of X-link &/or autosomal genes.  I believe this is often taken for granted by many swordtail breeders working predominantly with X-link double or top swords in which the majority of extension genetics are also passed in a tight linked gene complex.    

Few if any colors / phenotypes are the result of a single gene in guppies, more likely multiple genes by regulation(s).  The initial reciprocal breeding involved my Line 1 using a Blond Vienna Lower * JB.  It produced predominantly Abab males in both green and purple body mutation.  This high degree of autosomal dominance has maintained in subsequent Vienna breedings.  It likely expresses similar in JB.  You will notice below in these Asian Blau Vienna Lower normally “Orange” Wingean spots are still visible, with red pigment removed, solely by remaining iridophores which are the basis for patterns.  Prior to outcross my Line 1 Lowers did not contain Ze, yet barring is present in these F1 males.  Thus, further evidencing the trait was passed by JB females as an autosome.

Another visible trait found in both my Line 1 and the JB, is a very blue belly patch.  Resulting from blue iridophores it has been little modified by the presence of Ab.  Passed by males and females, this trait helps ad to the additional anterior color of the JB strain in combination with Ab.  A similar related effect can manifest above the lateral line on the shoulder.  However, it is more often evident in conjunction with a blue belly patch.

Asian Blau Vienna Lowers w/blue belly

The male below is multi generation pure from my Vienna Lower Line 1.  There seems to be a correlation between expression of the blue belly trait and EGI.  You will notice in this individual how the blue is also found in the lower peduncle.

Normal non Asian Blau Blond Vienna Lower w/blue belly

One of the hypotheses I wished to test for was the presence of Wild-Type Wingean Super gene traits being masked by Japan Blue.  To do so I employed a simple “fright test” and moved males directly from their tank into my photo tank without a period of acclimation.  You will notice that these males immediately revealed an orange spot in mid body.  While not visible in this photo a second spot was also present in the peduncle.   

 Japan Blue males without period of acclimation

Conclustions:

Within this JB strain in any given litter, both purebred and outcross with Vienna Lower, exists a broad range of phenotypic expression.  The overall basis for both the increased level of coloration and its intensity in this strain results from Asian Blau (Ab).  Additional color enhancement comes from a “blue belly” created by blue iridophores in conjunction with EGI.  A lack of yellow pigment or gold iridophores in the body further enhances coloration.  Each trait is independent of traditional Japan Blue (JB) and results from either X / Y sex link or autosomal genes.

  

 Asian Blau Japan Blue with X-link yellow

 Asian Blau Japan Blue with X-link yellow, including blond on the right

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Enjoy the strains you have labored to create?  Pass them around so others can do the same and maybe further your efforts.  Never know when you might want some back …

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Science as A Tool and Benefit to Guppy Breeders…

Science as A Tool and Benefit to Guppy Breeders…

© Alan S. Bias

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

January 11,  2012

Grey Vienna Emerald Lower with Blue Peduncle

Outcrossing is often offered as a cure all for a declining strain showing the effects of inbreeding. However, this is not the whole story. Just as the negative aspect of inbreeding can be described as inbreeding depression, outcrossing can result in outcrossing depression. What is “out-breeding depression?”  The answer can be found in one of the many tools available to the successful guppy breeder.  Science… Out-breeding depression is a loss of robustness due to reproduction among very dissimilar individuals; characterized as hybrid breakdown.

Out-breeding to a substantially different strain can break up the gene complexes needed to produce the initial traits a breeder is selecting for.  Science is not the cure all for a guppy breeder.   It is but one of many tools that can be used to balance out a successful breeding program for show, research, preservation or plain eye appeal.

Grey Asian Blau Lower with Z-Bar and Blue Peduncle

Understanding of traits we now take for granted such as blond (gold), albino, snakeskin, basic caudal extension all resulted from breeding experiments, analysis and testing of hypothesis.  Breeding guppies is already a science for those who take it seriously and are willing to admit it.

As a breeder I view guppies as a genetic puzzle to be decoded and expanded upon through phenotype.  Over the last 100 years our knowledge as grown by leaps and bounds.  Try to imagine the entire potential of the guppy genome.  You cannot.  Each of us is bound by our narrow focus on not only how we describe a quality guppy, but the breeding technique(s) we use to obtain them.  If a breeder is not careful self imposed limitations may hinder our interpretation of accrued knowledge from all sources and its possible uses.  To further compound events as breeders we often do not document results of our crosses very well. 

Breeders should consider the possibilities as they present themselves.  In example; a cull is not just an individual who fails in expectations.  You can still learn from it.  Did it come about from crossover or simple recombination of alleles?  Worse yet, will a gene complex inhibit your desired goals or is a form of gene regulation preventing it?

2.5 month old Asian Blau Blond & Grey Vienna Lower 

There are many elements that compose the whole of breeding domesticated guppies.  They include:  purebred, hybrid, research, enhancement, sale, and show to name a few.  Value of each is determined by personal interests.  Therefore, no single component or the resulting fish is of greater value than another in genotype if healthy and viable.  Breeder preference should not be misconstrued to suggest otherwise.  In each case the primary criteria for selection of potential stock should be limited to:  “Has it been bred toward goals that reflect my intended use and will it reproduce to type?”

Preservation, Improvement, and Promotion are considered the primary functions of a breed association. Showing is normally considered a by-product of purebred stock breeding, and is prohibited by some tasked w/preservation of gene pools to avoid judgment that results in inflated value.

Show stock is an expression of a particular phenotype and not always a reflection of breeding value.  Only a very small percentage of any purebred (registered) population is considered to be of show quality.  It takes the use of diverse breeding techniques by individual breeders to promote overall population health.  The value of purebred strains is to produce predictable results within itself and for infusion into that part of a population which does not.

Many authors continue to profess the benefits of out-breeding as a cure all for a declining strain showing the effects of inbreeding.  Normally I refrain from directly critiquing others, even when positive in intent.  Last month on one of my regular web rambles involving “Guppies” as part of the search criteria I ran across an article posted to the Malaysia Guppy Forum.  Originally published in the IFGA eBulletin Volume 7 # 7 July 2011, and titled “Follow the Best Genetics by Jim Alderson.”  It was originally a short article written by a prominent IFGA officer and breeder that has had me pondering ever sense.  Though vague in use of terms, it was not so much the content of the article that created issue for me as the perceived intent of summation.

As a linebreeder, in general, I could agree with much the author stated if his implication was his successful hybrid crosses are limited to highly inbred IFGA strains.  Broad based statements lacking clarity of definition are subject to a wide range of interpretation.  Crosses involving non IFGA strains or even dissimilar IFGA strains have the potential to be subject to out-breeding depression.  As a result, there are several conclusions offered by Alderson where I would disagree based not only on personal experiences as a breeder, but backed by scientific knowledge.

An example is: “Selecting more dissimilar fish will give you a wider range of variability and more hybrid vigor.”  Unless the intent was to introduce traits not already found in my strain, in this instance one could state that, “such an approach is just as likely to result in out-breeding depression in a fixed strain.”

In another quote, “A more sustainable approach is to use out-crossing to instill new genes into your pure lines and make rapid improvement in your stock. Remember, every time you out-cross you are improving the hardiness and disease resistance of the the fish as well.”  One could easily state that, “such an approach is just as likely to result in out-breeding depression in a fixed strain by reducing or eliminating positive benefit derived from already existing co-adaptive gene complexes for disease resistance.”

Grey Schimmelpennig Platinum Lyretail

While we lack corresponding “registration papers,” as found in animal breed associations, with line-bred Guppy strains an old adage in the Pedigree Livestock World is very applicable.  It simply states, “A pedigree is only as good as the breeder who produced it.”   This is a personal preference based on not being interested in creating hybrids for show.  As a result I seek out methods that will reliably produce sound pedigreed breeding stock and promote the results.  I would not take a route that derives short-term result from long-term failure.  Genetic dead-ends are of little value in a breeding program.

Some years back I wrote a couple articles for the sheep world that were published by several breed groups:   Breeding Strategies and Genetic Manipulation ~and~ Breeding Strategies and Genetic Consequences.  Recently, after review, retired biology professor Richard “Rick” D. Squire, Ph. D., and now active guppy breeder felt I should rework them for the benefit of other breeders.  Here are the links to each as rewritten:    

                                                                                                                                      

Breeding Strategies and Genetic Manipulation in Guppies

~ and~

Breeding Strategies and Genetic Consequences in Guppies 

There has always been a view in show circles that claims many new breeders are successful until they step out of the box, break from established practice and try to do things on their own.  This seems to indicate much initial success results from starting off with reliable strains produced by those breeders who utilize all tools available.  Tools which can provide definition to the more static results we often observe as breeders to provide forethought in planning matings.  Science is one of them. 

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In the end what was in Alderson’s summation that was so perplexing it led me to spend several weeks procrastinating a response?  It stated:  Guppy genetics is not a science. Guppies are a tapestry that we can learn to paint with a few genetic principles, trial and error, and records. Those who claim to study guppy genetics do so by making the crosses and dissecting the results, not by predicting the outcome in advance, claiming to have discovered the inheritance of a new trait, until the next cross is made that does not follow the rules. Breeding guppies may someday be a science, but I will be pushing up daisies by then.

Having thought about this statement for some time, it dawned on me what I found so disconcerting is that a prominent IFGA officer and breeder would not only appear to frown upon, but downplay one of the organizations founding principles as stated: 

IFGA Constitution

ARTICLE 2 – PURPOSE AND OBJECTIVES

Section 2.1 – Purpose

            2.1.1    To promote interest in, and scientific knowledge about guppies.

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Misconceptions based on Phenotypical Observations

Misconceptions based on Phenotypical Observations

© Alan S. Bias

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

I think alot of the misconceptions in Guppy Genetics by hobbyists are based on observations derived from the wrong starting point.  Huh???  How can I say this being an acknowledged livestock breeder who breeds by eye?  Take a peak at the fish below and make an initial assumption on them as a breeder and keep it in mind.  Then, let us back up in time.

Most traditional livestock breeds are defined on a very narrow range of phenotype with broader emphasis on balancing unique specific traits.  The combination of which not only allowed the breed to survive in its native habitat, but also allowed the breeder farmer to do likewise.  Much like any wild species left to its own devices such as Poecilia Reticulata - The Guppy.

Purple Vienna Lower Swords in both body and fins

Too my initial dislike, I've come to the conclusion that guppy strains take the form of commercial breeds of livestock.  Most strains survive and thrive short-term based on fad.  Face it, they evolve by breeder efforts and then remain in existence from further interest by future breeders through marketing and availability.  Very few static strains are maintained long-term by scientists in labs or breeders who persist with them for many years.


The number, types and evolution of strains is in continual state of modification, much like any other commercial breed of livestock.  Here today and gone tomorrow.  Little different than women's shoes or men's ties.  In many minimal value is placed on long-term survival traits.  Modern guppy strains are often not unique in a sense of survive-ability, just expressed phenotype.   


Is this all bad?  No.  To date it has allowed for a continuing evolution in the diversity of phenotype in most of the world.  Think about it.  For the past 100 years breeding and showing of guppies has been based near exclusively on phenotype.   Those that have built in sustainability and not just the latest greatest fad will continue to influence not only further development, but our understanding of the genetics behind it.

Green Vienna Lower Swordtail with yellow finnage

Complex modern guppy strains are often the product of  not only sex-linked traits, but in combination with several autosomal traits.   Is it possible to create and maintain diverse & often delicate phenotypes as strains with built in hardiness?  The answer should be, Yes.  To do so one has to abandon the concept looking at a guppy initially, if not solely, from the standpoint of phenotype.  Ah,  I did it again.   


I am a livestock breeder.  A traditional one at that.  As such I breed by eye and experience.  The experience is an accumulation of knowledge passed down from others and first hand, in conjunction with that acquired from sound scientific exploration.  The latter more often than not the result of others efforts.  Face it most hobbyists, myself included, lack the dedication to implement a breeding program based on scientific method.  Much less document and analyze the results by true scientific principles.

Green Vienna Lower Swordtail with Asian Blau & yellow fins

Good breeders will always breed by eye and intuition.  Successful breeders of stock throughout history have done so.  Of late I also incorporate much more acquired scientific knowledge into the decision making process.  To borrow a coined phrase of another guppy breeder, one must become " A Guppy Designer."  Did these early stock breeders do the same?  Yes, they did without setting out to do so.  The difference is they were fewer in number and likely had a natural ability to do so in a time of limited scientific knowledge.  This through the power of observation, trial and error.  A practice the continues to this day and will do so into the future.  It is an integral part of livestock breeding.  We are in the business of genetic manipulation.  Not the creation of, as the genetics are already in place.

Green Vienna Lower Swordtail with blue peduncles & yellow fins

A breed standard is usually based on expressed, or more often visualized phenotypical traits and has its merit.  It allows for fixed descriptors that are easily interpreted by all breeders.  A good starting point with some common terminology.  Inadvertently, it is also where problems start to arise.  We do not all see color in the same way.  We do not convey in expression what we see in the same way.  We also do not light our fishroom in the same way.  Then, we send our fish to shows that are rarely lit in the same way.


A breeder must be able to develop an understanding of the basis of guppy genotype.  Not only for color and pattern, but also for less visible traits.  These would include fertility, disease resistance, longevity, docility to name but a few.  By doing so you will be able to not only understand how your particular strain evolved, but also how to maintain and improve upon it.  Modern guppy strains are far to complex to do otherwise.

Purple Vienna Lower Swordtail with Asian Blau & yellow fins

Often a hobbyist bases decisions on observations of a specific phenotype and not what genetic design it took to create it.  This perception is often instilled by show standards that in effect ignore the principles of genetics.  A sort of "what you see it what you get" approach.  After many years of breeding largely to a set standard for swordtails I found my fishroom in a state of stagnation.  Though always reserving 10-20% of my tanks for exploration, far too many fish were simply being culled on the basis of not meeting standards.  Little improvement in strains and much more emphasis put on trying to just maintain and produce a couple good fish to show next year.

Grey Bodied Vienna Lower Swordtail female with & yellow fins

About 10 years ago I decided to take a different approach and let the genetics decide much of when, where and how my fish evolved.  To start with I made a drastic decision to reduce not only the type of strains I raised, but the number.  With only 60 tanks at the time I saw no other practical approach.  These days I am only running 40 tanks and even larger collection of genotype.  Largely Vienna Emerald Green (VEG) and Schimmelpennig Platinum's.  In part compatibility of females has allowed for  a reduction in the number of tanks.  
  
At some point a balance must be maintained to allow for selection of breeders that will produce, sustain and improve upon existing strains when attempting to create new ones.  A balance that derives from genetic understanding combined with a breeders eye in effort to produce not only beautiful phenotype, but viable strains with built in hardiness and disease resistance.

Green Vienna Lower Swordtail with Asian Blau & yellow fins

That brings us back to the initial intent of this article.  Based on genotype how would you describe the fish in the very first photo?  Without some understanding of genotype it would be very easy to declare a host of color descriptions and possibly assume the result of a hybrid litter.  These fish will breed true to their type.  All are gold (blond) or grey  in either green or purple body with about half showing the effects of autosomal Asian Blau (Ab) .  While they may be just as diverse in phenotype as genotype they are still basically all one in the same fish.  In fact, siblings from a single litter in a line of my Vienna Type Lower Swordtails.

Over a decade ago I set to undertake a better understanding of the genetics involved in my fish.  A process that is ongoing.  The knowledge gained has  produced a diversity of type in homozygous or heterozygous states.   Resulting in a much greater stability in the fish.  By doing so I hopefully will have created strains that exist into the future.  In a more static state, that mimics a time of traditional breeds and not just a fad...

Green Vienna Lower Swordtail with Bar & yellow fins

~~~  Often the most overlooked tool available to a breeder is an exchange of knowledge and the ability to consider what is offered by others without prejudice based upon your own knowledge.  Then let things stand or fall on their own merit or lack thereof  ~~~

Hemiray Bifurcation and its effect on swordtail caudal selection...

Hemiray Bifurcation and its effect on swordtail caudal selection...

© Alan S. Bias

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

Hemiray Bifurcation can quickly be defined as:  "A division or fork in the rays of male and female  guppy fins."

Swordtail Female with Hemiray Bifurcation evident

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.

Bifurcation and effect on fin edge

The problem with this desired end result stems from the very nature of the processes involved in the growth of fins.  As a rule a guppies finnage including caudal, dorsal, pectoral, anal and pelvic have been regulated by gene complex through the eons to maintain a well defined shape and structure.  Fairly smooth edges and round in most fins.  Though, points are considered normal as evidenced in the shape of vent fins and small swords in otherwise round caudals.  One might say, "Evolution has made it easy for us to keep and breed guppies as long as one stays within the confines it has established."

Effect of bifurcation on round caudal

The trouble is few of us as Guppy Breeders have chosen to do so over the last 100 years.  Not only do we attempt to force modifications into color & pattern, but also fin shape & extension.  For most of us this is limited to a number of established configurations in the caudal and dorsal.  Exceptions would include extension genetics involved with  long-fin phenotypes variously referred to as;  Berlin - Geissen - Ribbon - Swallow.  In all instances you will still be forced to make decisions as a breeder based on the influences of Hemiray Bifurcation.  At first the process of enlarging a naturally occurring fin type, ie swordtails, seems like it would simply involve traditional breeding techniques with a sufficient number of tanks to let trial and error work its course over a number of generations.  After all, we are simply trying to use extension genetics to force more growth into hemirays already part of an occurring tail shape.  Or are we?  

Type 1 Swordtail

Type 2 Swordtail

This is where the bifurcation comes into play.  It is the root cause that will lead to a breeder culling many of the Swordtail males produced in both fixed strains and outcross.  Most swordtail strains not only include a lengthening, but also an encompass an increased number of rays.  To this day the actual genetic makeup of swordtail guppies is still the topic of hot discussion and alot of speculation with breeders around the world.  From my experience Swordtails are comprised of two distinct types.  Type 1, in general, result from several genes (more likely groups of genes) either individually or in complex to include Elongatus, Aureus, Lineus and Armatus.  Producing not only Top & Lower Swords, but also Double Swords as evidenced by those who exhibit an imbalance not only in shape, but also growth between the upper and lower swords.  Type 2 is likely the result of  the Double Sword gene (Ds) and a lack of Pigmentierte caudalis (Cp).

Type 1 Swordtail showing
about 1/2 of mature length

As a guppies fins continue to grow each hemiray at a fixed point will split and fork in two.  Under normal conditions it will then continue to grow for a fixed length and again fork.  This process will continue for as long as each individual fin ray grows.  Regardless of shape.  Herein, lies first issue we try to circumvent as Swordtail breeders.  How do you force a fork into a point?  The answer is you cannot.  Though, through selection you can create the illusion of a point.  In theory this should be pretty easy as we are dealing with a limited total number of hemirays.  In practice each is an independent entity with a purpose of it's own.  Through a combination of consistent selection for the best tail shape it can be done.  But keep in mind you are also trying to load balance your other desired traits for color, shape, size, pattern, growth, maternal, longevity to name but a few.  If you concentrate heavily on tail shape then these areas may suffer.  It is often necessary to utilize a breeder male that has a weaker point or lessor length.  Not only to maintain your established strain, but more often to identify and create additional phenotypes.  

Lower Swordtail "pencil tail" 

Lower Swordtail not yet mature

If you work with Swordtails long enough you will realize that many are more often "camouflaged" Lyretails that have been forced into a swordtail configuration via breeder selection to meet a standard.  Why, you ask?  It is much easier to create the illusion of a nice clean point from fewer hemirays.  I find good swordtail caudal extension contains a larger number of colored  & extended rays starting from at rays 3-5, with an increasing number all extending to the final point.  The best swords are often composed of a single ray or two forming the entire outside length.  Many lines of swordtails to maintain length and clean points have evolved into "pencil tails" with as few as 2-3 total rays showing extension and lacking color on the interior side.  Avoiding clear rays on the interior of the swords will help alleviate some issues. 

Lyretail

In contrast many Lyretail's extension start from rays 5-7 with extension in only the next 2-3.  Initial Lyretail rays can taper off into those rays that lengthen and extend to the final point, often with those  on the interior reversing the process and shortening.   A prime example are Schimmelpennig Platinum's.  Both pattern and tail shape are closely linked from a complex of Y-link and autosomal traits.  It is easily maintained as a true Lyretail and possible to create a Schim. Double Sword.  Still most of those offered by breeders for sale or exhibition as Double Swords are frequently Lyres.  Examination of which rays form the extension under magnification will confirm this.  While the Schim. Lyres have thick rays and stable extensions, the doubles are very prone to splitting and even stray growths.  What always perplexed me is why?   They reportedly evolved from mutation within Vienna Emerald.  As a rule VEG strains have very stable fin type.  After 10 years of breeding Schims the only hypothesis I can offer is it results from the combination of Ds and metal in the males.   

Lower Sword exhibiting weakness at bifuracations

One of the common problems that arises in a swordtail is fin splitting on the interior portion of a sword, ie the top side of a lower or the under side of a top.  This results from weaknesses created where each ray forks.  Having put quite a few under magnification, it is rare see a split that happens any distance before a fork.  Just at a fork or shortly thereafter is the norm.  It is often difficult to distinguish splits resulting from genetic weaknesses and those from environmental issues such as frequent fighting between males.  The prior should be frowned upon in breeder selection and preferably culled from a program.  While splits resulting from environmental issues will usually heal and continue to grow it is not without consequence on males intended for exhibition.  Hemiray growth after an injury, be it natural or surgical, follows a different course from rays unaffected.  Not only will the circumference of  rays be smaller, the natural segments of each will not be evenly paired with other rays.  Additional bifurcation is also reduced if not eliminated in damaged rays.  This is often visible in Delta strains in which ragged caudal edges have been surgically altered.  The ends of the caudal are clean from new tissue growth surrounding rays that have regrown without forks.  Given time new color cells will migrate to the areas of new growth and darken them.

Young Vienna Type Double 

For those of your wishing to read further on Hemiray Bifurcation a number of published studies dealing with Zebra Fish are readily available.  Two I have found of interest are:


1.  Growth Control in the Regenerating Zebrafish Ontogenetic and Fin

Stephen L. Johnson* and Paul Bennettt


2.  Position dependence of hemiray morphogenesis during tail fin regeneration in Danio rerio

C. Murciano a, J. Pérez-Claros b, A. Smith c, F. Avaron c, T.D. Fernández a, I. Durán a, J. Ruiz-Sánchez a, F. García a, J. Becerra a, M.-A. Akimenko c, M. Marí-Beffa a, 


  

Breeding to a defined standard or personal goal is often

 what initially attracts us to guppies as a breeder . 

Embarking upon a genetic understanding of those fish we choose to cull

and those we decide to retain within a breeding program 

often makes the difference in breeder perseverance...

World Guppy Contest 2011 in Boston

News

WORLD GUPPY CONTEST 2011 October 14th to 16th, Boston/USA For more information Including Sponsorship and Exhibitor Information, Auction Rules and Registration forms visit the convention website at http://GuppyCon.com  Still some time to ship & show your efforts and help support those of others.  No entry fees are required if you donate your fish for auction.