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Angelfish
Genetics
by:
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of
Mellow Aquatics,
P.O. Box 126, Garrett Park, MD 20896
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Aquatics
Introduction
1. Angelfish gene mutations categorized according to characteristic group.
2. Dominance, phenotype, and genetic interactions of angelfish gene
mutations.
3. Phenotypes resulting from 3 or
more Mutation groups in angelfish.
4. Phenotypes of angelfish not explained by Mendelian Genetics.
Introduction:
This page provides information about angelfish genetics to Angelfish Hobbyists trying to
predict or target the production of specific angelfish varieties. It also proposes notations for communicating angelfish genetics. These notations are consistent with notations
many Angelfish Hobbyists are already using. Unproven genes are not included. It is possible that proven genes which we do not have experience with are not included.
In Table 1, eleven gene mutations of angelfish are categorized according to
“characteristic groups” that operate independently. We define a characteristic group as a set of apparently independent alleles or in the case of gold marble, possibly linked
alleles. All the alleles in a characteristic group likely reside on the same chromosome. Mellow Aquatics lists angelfish mutations by characteristic group in the same order shown
in Table 1:
Upper case symbols designate genes which are dominant or incompletely dominant. Lower
case symbols designate genes which are recessive.
For each characteristic group, a plus sign (+) is used to symbolize the corresponding wildtype
gene at the locus of the gene mutation(s) or the lack of a corresponding wildtype gene. Therefore, each group has its own “+”.
In communicating the mutations carried by a particular angelfish, the genes for the 7
characteristic groups are presented in the same order as in Table 1. Thus, an albino pearlscale veiltail would have the following notation: +/+ +/+ V/+ +/+ +/+ p/p a/a. However,
when an angelfish only has mutations in the first few groups, the list need only include groups up to the last group in the sequence. For example, an angelfish with color mutations
for gold is designated: g/g. All other genes after the color group would be understood to be wildtype; therefore, g/g means g/g +/+ +/+ +/+ +/+ +/+ +/+. An angelfish with a single
gene mutation for veiltail is designated: +/+ +/+ V/+ which means +/+ +/+ V/+ +/+ +/+ +/+ +/+.
The next 3 tables, Tables 2. through 4, present draft summaries of angelfish genetic information.
This information is based on our experience, understanding, and reading of the popular tropical fish literature. The information is not based on scientific studies. These Tables
are meant to be used by hobbyists and can be expanded based on different Angelfish Breeders’ experiences.
Table 2 presents dominance, phenotype, and genetic interaction information.
Table 3 presents phenotypes that result from the involvement of 3 or more characteristic
groups. We could only think of one combination based on our experience. Perhaps you know of others?
Table 4 presents phenotypic characteristics that do not appear to be genetically
controlled by discreet genes operating according to Mendel’s law.
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Table 2. Dominance, Phenotype, and Genetic Interactions of
Angelfish Gene
Mutations |
|
Order |
Characteristic Group |
Mutation |
Symbol |
Dominance |
Phenotype |
Interactions between Groups |
|
1st
|
color |
marble |
M |
incompletely dominant |
M/M |
black and white marbled |
M/M, M/g, M/gM repress the phenotypic expression of stripes |
|
M/+ |
dull marbling, stripes are expressed although they appear lighter |
|
M/B |
?* |
|
M/g |
marbling with more pronounced black and white contrast than M/M |
|
M/gM |
marbling with more pronounced black and white contrast than M/M |
|
black |
B |
incompletely dominant |
B/B |
jet black |
B/B masks wildtype stripes (+/+) in adults but this is probably not a genetic interaction |
|
B/+ |
black lace, a coloration which is “intermediate” between silver and black |
|
B/M |
?* |
|
B/g |
black not as dark as B/B, stripes may show through especially in juveniles |
|
B/gM |
black not as dark as B/B, stripes may show through especially in juveniles |
|
gold (new gold) |
g |
recessive |
g/g |
gold |
g/g and g/gM repress the phenotypic expression of all stripes, h/h, Sm/Sm and Sm/+
g/M represses the phenotypic expression of stripes |
|
g/+ |
silver |
|
g/M |
marbling with more pronounced black and white contrast than M/M |
|
g/B |
black not as dark as B/B, stripes may show through especially in juveniles |
|
g/gM |
gold marble |
|
gold marble |
gM |
gold (g)
incompletely dominant (M) |
gM/gM |
gold marble |
gM/gM and gM/g repress the phenotypic expression of stripes, h/h, Sm/Sm and Sm/+
gM/M represses the phenotypic expression of stripes |
|
gM/+ |
silver with black marbling |
|
gM/M |
marbling with more pronounced black and white contrast than M/M |
|
gM/B |
black not as dark as B/B, stripes may show through especially in juveniles |
|
gM/g |
gold marble |
|
2nd
|
stripes |
stripeless |
S |
incompletely dominant |
S/S |
blushing
|
S/S causes g/g to be white instead of gold, causes the g of gM/gM or gM/g to be white but does not affect black
marbling
Z/Z and Z/+ cause a zebra pattern to break the homogeneity of the black pattern in B/B, B/g, and B/gM
Z/Z and Z/+ cause Sm/Sm and Sm/+ to have a more speckled pattern? |
|
S/+ |
stripeless (ghost) |
|
S/Z |
speckled or clown |
|
zebra |
Z |
dominant |
Z/Z |
zebra |
|
Z/+ |
zebra |
|
Z/S |
speckled or clown |
|
3rd |
fins |
veiltail |
V |
incompletely dominant |
V/V |
double veiltail (superveil) |
|
|
V/+ |
veiltail |
|
4th |
half-black |
half-black |
h |
recessive |
h/h |
half-black |
|
|
h/+ |
silver |
|
5th |
smokey |
smokey |
Sm |
incompletely dominant |
Sm/Sm |
chocolate |
|
|
Sm/+ |
smokey |
|
6th |
pearlscale |
pearlscale |
p |
recessive |
p/p |
pearlscale |
|
|
p/+ |
normal scales |
|
7th |
albino |
albino** |
a |
recessive |
a/a |
albino |
a/a represses dark pigmentation of color, stripe, half-black, and smokey group genes |
|
a/+ |
no effect |
|
* no experience with the B/M combination
**My understanding is that albinism in other animals is actually coded for by more than one gene, each gene
coding for a biochemical step in the synthesis of melanin. However, most angelfish breeders treat albinism as a single gene. This may be appropriate from a practical breeder’s
perspective if the multiple genes for albinism exist and do not operate independently (i.e. they are located on the same chromosome).
Notes: “streak” gene information needed for inclusion in this table.
Information on the intereaction between color group genes and the smokey gene needed. |
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Table 3. Phenotypes Resulting from 3 or more Mutation groups in Angelfish* |
|
Genotype |
Phenotype |
|
+/B ZZ */* +/* +/Sm1 |
cobra pattern2 |
|
1An asterisk (*) is like a wildcard in that it signifies that any gene for the group
could be present and still result in the designated phenotype.
2We have produced these beautiful fish by crossing a chocolate leopard (+/+ Z/Z +/+ +/+
Sm/Sm) with a double black double zebra (B/B Z/Z).
Note: The cobra has been previously defined as +/+ Z/Z +/+ +/+ Sm/+ grown with a long photoperiod. We prefer to
define a variety by appearance and discuss separately the genetic and environmental variations that can be used to produce the variety. In this case we found another way
to produce a fish that looks just like the cobra that was grown with a long photoperiod. |
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Table 4. Phenotypes of Angelfish not Explained by Mendelian Genetics |
|
Phenotype |
Discussion |
|
Orange Pigmentation |
Orange pigmentation appears in many varieties of angelfish including silver angels (+/+). However,
it shows up best in white areas of Koi angels (gM/gM S/S or gM/g S/S) and White Blushing Angels (g/g S/S) . Orange pigmentation is naturally concentrated in the crown area
(dorsal area of body between the mouth and the base of the dorsal fin) but can also occur on any body part. This characteristic does not appear to behave according to Mendelian
rules.
The propensity of the orange characteristic to be enhanced is similar to the enhancement propensity
of black marbling in marble, koi, and gold marble angelfish. In these 3 varieties, black marbling can be selected to produce fish that are almost all black. Likewise, in Koi,
orange can be selected to produce fish that are all orange.
It seems that the expression of orange may be genetically related to marbling based on our
experience of enhancing orange by out breeding to marble angels and backcrossing. Also, Koi that are over 85% orange with very little marbling can produce fish with extensive
marbling. However, the orange pigmentation of koi seems to be linked somehow to the gold marble gene because out breeding to pure white blushers with no orange (g/g S/S),
followed by backcrossing the offspring, does not produce orange pigmentation. Therefore, the mechanism by which out breeding to marble angelfish enhances coverage with orange
cannot be explained
Orange pigmentation can be selected in white blushers too, although the results of this have not
produced fish as orange as the best orange koi. One form of orange pigmentation in white blushing angels is the orange crowned white blusher which has a distinct orange crown.
This may be what some angelfish breeders call a sunset blusher. We have also produced fish in which the orange crown was transferred to the ventral area as orange streaks
extending into the ventral fin. Recently a fish was produced in our hatchery with an orange patch which we believe may have been the result of “crossing over” from the
chromosome carrying the gM gene in orange koi angels to the g gene. |
|
Stripe pattern in gold marble angelfish |
The presence of one or more apparent black stripes or partial stripes in gold marble angels
suggests that an interaction between M of gM and the wildtype stripe (+) may exist. However, breeding fish with this characteristic does not appear to increase the strength of
the phenotype or the frequency of its occurrence in the offspring. In fact, our experience with breeding gold marble angelfish with "marble stripes" resulted in broods without
any occurrence of the characteristic. |
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Swallowtail |
This characteristic is a partially split anal fin which shows up sporadically in many angelfish
hatcheries including ours. We have produced viable offspring when breeding 2 fish with the swallowtail characteristic, but none of the offspring were swallowtails. I have heard
that some normal finned parents throw a few Swallowtails in every brood. If this is true, it suggests that the swallowtail characteristic has a genetic basis and is not just a
developmental abnormality. If this is true, it suggests that this characteristic might be transmittable but not apparently according to Mendel's Law.
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