Homozygous Asian Blau Vienna Emerald
© Alan S. Bias
Permission granted for
nonprofit reproduction or duplication of photos and text with proper credit for
learning purposes only.
Sept 2, 2013
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| Homozygous Asian Blau Vienna Emerald |
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.
Is this a good enough reason for show
breeders or those researching specific traits to casually discard such an
unassuming phenotype? Can these fish be
of use to IFGA and other showing breeders programs for research and improvement? Most assuredly, by fostering an understanding
of genetic principles from an extreme perspective, In turn increase iridescence
in solid color pigment strains such as red, green, blue and purple. It can also lend a better understanding into
the complexities of modern platinum strains, which in conjunction with Ab, are now
frequently infused into solid strains such as modern Yellow Delta’s.
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| Homozygous Asian Blau Vienna Emerald female |
Discussion:
We can ascertain red pigment is not
actually removed, as it returns in sibling breedings and outcross to non-red
color pigment strains. This indicates
red color pigment remains present in genotype of homozygous Ab & heterozygous Ab individuals. European breeders routinely refer to this
practice of using Asian Blau as a “Blau cheat” to artificially create “Blue”. Ab in the prior examples should be looked
upon as nothing more than a genetic tool for removal of red color
pigment. It is no different in practice
than outcross to a non-red strain; only in genetic principle does it
differ. For the most part yellow color
pigment, while sometimes reduced, is normally left intact with infusion of Ab.
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| Homozygous Asian Blau Vienna Emerald |
In all strains, to include prior examples,
homozygosity for Ab will reduce male caudal structure in X-link Caudalis Pigmentierte (Cp) Delta
Tails, Y-link Lower Swordtails (LS) and X-link Double Swordtails (DS) to a
shape resembling a roundtail with extension. Though, some weak delta tails
present, more often than not homozygyous Ab definitely has overwhelming impact
on Cp.
Again, this is via epistasis and not removal of affected traits. In example:
I routinely test breed homozygous Ab Vienna Emerald LS, as
pictured above, to non-Ab or heterozygous Ab sisters. The resulting heterozygous Ab or non-Ab male
offspring exhibit 100% Vienna LS phenotype with full extension as in photos below. While sons homozygous for Ab continue to
resemble their sire. If find it very intriguing that Ab can have little or no effect on dorsal extension. This further lends support that most caudal and dorsal extensions are independently regulated, unless in true complex.
Asian Blau is
considered an “Autosomal Partially Domiant Trait”. Simply stated, it expresses to a degree, ie.
alters phenotype, in heterozygous fashion.
In my Vienna Swordtail breedings this occurs in at least three primary expressions; removal of red pigment, reduction of black
melanophores, and amplification of iridophores.
This is visibly manifest in both grey and blond (IFGA gold) fish to
nearly equal degree.
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| Vienna Emerald Lowersword |
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| Heterozygous Asian Blau Vienna Emerald Lowersword |
The focus on this article is to point
out to breeders that homozygous Ab expression can be used as a case study, resulting
in a form of beauty with fertility and hardiness. In turn, can be used in heterozygous form by
those breeders with visual acuity to further advance strains. For further
reading on heterozgous Asian Blau expression you may wish to read:
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Infusion of Ab into strains bred for
predominantly flat color pigment over iridophores can result in heterozygous Ab
phenotypes with extreme eye appeal as given in example and seen above. Breeders often combine additional autosomal
recessives for pattern modification requiring homozygous expression;
fragmentary snakeskin, Z-bar, metal (Mg), blond (b), albino (a), pink (Pk).
Autosomal Partially Dominant Traits are often much weaker standalone in homozygous form than traditional
Autosomal Recessive counterparts, such as golden (IFGA bronze) or albino. When Ab combines in homozygous form, in
conjunction with additional homozygous recessives, it can result in weak or stunted
fish. Linebreeding is not advisable. While traits such as golden are considered
recessive, they do, in fact, visibly alter expression in heterozygous form.
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| Homozygous Asian Blau Vienna Emerald |
Homozygous Ab is no
different than any other homozygote expression.
It requires diligence on part of breeders to both bolster hardiness and
phenotypical expression. One way to
accomplish this requires a breeding program geared toward iridescence over
color pigment, and yellow color pigment over red. As mentioned Ab will not remove yellow
pigment in finnage in heterozygous form, but homozygous Ab will. Leaving visible only certain classes of black
melanophores and metallic iridophores in; blue, red/purple, yellow/green. This will create a genotype allowing for
colorful expression.
.jpg) |
| Luteus (by Winge) |
Research has shown yellow color pigment
has a close relationship with black melanophores in multiple recognized complexes. It is easily seen in traits such as Luteus
(Lu) and Flavus (Fla). End result, when
one is present so is the other. In delta
strains this often manifests in the form of black trailing edges on finnage in
strains such as grey body HB Yellow or Yellow Deltas. In blond (IFGA gold) counterparts melanophores are
reduced, leaving areas devoid of black.
Yellow Swordtails express no different, and the effect is often more
visible resembling wild-type
.jpg) |
| Flavus (by Winge) |
While heterozygous Ab will in effect
remove black from phenotypical expression in these traits, as evidenced in prior heterozygous grey Ab Vienna LS photo, it can have just the opposite effect in homozygous
expression. It will both collect and
amplify regions of black. The addition
of variegation, a trait involving black melanophores, is also disrupted by Ab. As is Nigrocaudatus (HB) and Cp. In each case, there is a correlation with a
disruption of the expected effects of a specific trait in conjunction with Ab.
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| Flavus - Ni - Cp (by Kirpichnikov) |
Concentrated black melanophores in homozygous
Ab fish are also highly motile in nature.
This extends to all zones of regulation in body, caudal and dorsal. While masked via epistatic effect of
homozygous Ab, yellow color pigment is still very much present in genotype. As regulation is controlled in several distinct
body segments, each independent of the other, expression can vary immensely
from minute to minute when courting or feeding.
In analogy, a poor man’s Cuttlefish if you will.
Summary:
With effort Homozygous Ab guppies, while
unlikely to ever place in a sanctioned show, can have a beauty of type all to
themselves in the realm of established strains.
I have always thought of them as incorporating the wispy and delicate
form found in Japanese “Medaka”. Of much
more importance is the ability of Ab to educate visually inclined breeders and
show the results of “cause and effect” found in their Ab show Guppy strains. All it takes is a little patience, knowledge
and a good eye. We are often so pressed for space on a quest to save and select
superior breeders for the next generation; we fail to digest what those who
fall short have to offer.
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| Homozygous Asian Blau Vienna Emerald |
Color
Plate References:
Winge, O
& Ditlevsen, E. (1947), “Colour Inheritance and Sex Determination in
Lebistes”, Carlsberg Lab, Copenhagen, Valby.
Kirpichnikov 1981 – “Genetic Bases of
Fish Selection”, Translated by G.G. Gause, Springer-Verlag, Berlin Heidelberg,
New York.
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Guppies have always been referred to as a
Geneticists Dream. One day our Genetic Toolbox will likely realize a finite
number of traits to work with. For now
they keep appearing around the world in breeder tanks in ever increasing
combinations.
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