Have you ever considered breeding cats of a new or unusual color or
pattern? Been interested in peoples lyrical descriptions of chocolate and lilac
smokes, tabbies, silvers and bicolors but not known enough about how to produce them?
Follow along some examples while we outline breeding plans capable of producing these (and
other) colors, starting with crosses of (a) chocolate point by silver, (b) chocolate point
by brown (genetically black) tabby, (c) chocolate color point carrier (CPC) by blue smoke
lynx point, and (d) chocolate CPC by blue and white bicolor. To begin with, since none
of these colors are sex-linked it makes no difference which parent is male and which is
female. Small letters designate recessive genes; capital letters signify dominant genes.
A. Chocolate point by silver mating
The genotype of these parents may be designated thus:
Chocolate Point
Silver
aa removes agouti banding |
AA agouti banding (stripes) |
bb brown pigment |
BB black pigment |
cc Siamese coat pattern |
CC full coat color |
DD dense coloration |
DD dense coloration |
ii non-tipped coat |
II inhibitor gene - tipped coat |
In this example it is assumed that neither parent carries the d gene for
dilute color; thus none of the offspring of this mating can be dilute. In order to produce
a dilute kitten (blue or lilac) both
parents must have at least one dilute gene. If the chocolate point parent has thrown any
dilute kittens or has a dilute parent it must carry the dilute gene. Because most silvers
are color bred the silver is unlikely to carry the dilute gene; hence even if
the chocolate point is heterozygous (Dd) the homozygous (DD) of the silver would assure
that all kittens would be (D-) dense. Under the above assumptions all the offspring of the
above breeding will have the genotype Aa Bb Cc DD Ii and their phenotype (appearance) will
be as follows (taken gene by gene):
Aa - stripes
Bb - black pigment
Cc - full coat color
DD - dense color
Ii - tipped coats
They would be described as silver tabbies; eye color is usually hazel. This first
generation can be pretty boring to those who like to see color variation in kittens, but
when two cats of this genotype are bred to one another there are more possibilities:
Probable offspring from crossing of two heterozygous silver tabbies:
Genotype Phenotype Summary
Genotype
Phenotype
1/4 AA agouti-striped |
3 / 4 striped |
2/4 Aa, Aa agouti-striped (heterozygous) |
|
1/4 aa non-agouti (no stripes) |
l/4 solid - (no stripes) |
1/4 BB black pigment |
3 / 4 black pigment |
2/4 Bb, Bb black |
2/4 Chocolate carriers |
1/4 bb chocolate brown |
1/4/ Chocolate brown |
1/4 CC full coat pattern |
3/4 full coat pattern |
2/4 Cc, Cc full coat pattern (color point carriers) |
2/4 full coat pattern (colorpoint carriers) |
1/4 cc Siamese coat pattern |
1/4 Siamese coat pattern |
4/4 DD dense pigment |
No blue, lilac, dilutes |
1/4 II tipped coat |
3/4 tipped coats |
2/4 Ii, Ii tipped coat (heterozygous) |
|
1/4 ii non-tipped coat |
1/4 non-tipped coats |
Because there is no linking among the above characteristics there is no way to control
whether a chocolate kitten resulting from the above breeding would also have (a) a tipped
coat, (b) the Siamese coat pattern, or (c) tabby stripes. If we wish to know the genotype
of the chocolate kitten, the chocolate kitten is most likely (75%) to have a tipped coat
and (75%) stripes, i.e. to be a chocolate tabby smoke, or it could instead be a chocolate
point (bb cc), a chocolate lynx point(A- bb cc), a chocolate smoke lynx point (A- bb cc
I-), a solid chocolate (aa bb C- ii), or a chocolate smoke (aa bb C- I-).
B. Chocolate point by brown tabby
One sometimes hears people recommending that one cross chocolates with brown tabbies to
achieve other colors of chocolates. One might capitalize on the nice type of the brown
tabbies by so doing, but, because the brown tabby does not have the inhibitor gene (I-)
which causes tipping and removes the gold band there would be no smoke or
tipped cats resulting from such a cross. Otherwise the results would be
similar to the results from crossing a chocolate point with a silver, except that the
yellow agouti banding would remain, producing golden tabbies rather than the tipped coat
of the silver tabbies. Chocolate goldens could then be produced by breeding these golden
tabbies which carry the chocolate gene to solid chocolates.
C. Chocolate CPC (dilute carrier) by blue smoke lynx point (chocolate carrier)
If one wishes to produce varieties of lilac kittens as well as chocolates it is necessary
to have at least one dilute gene in each parent. The cats described above have the
following genotypes:
aa bb Cc Dd ii X Aa Bb cc dd Ii
2/ 4 Aa Agouti (stripes)
2/4 aa Non-agouti (no stripes)
2/4 Bb Black pigment
2/4 bb Brown pigment (chocolate)
2/4 Cc full coat color
2/4 cc Siamese coat pattern
2/4 Dd Dense pigment (black or seal pt.)
2/4 dd Dilute pigment (blue or lilac)
2/4 Ii Inhibitor gene - tipped coat
2/4 ii non-tipped coat
Note that for each gene we are combining a homozygous recessive (e.g. aa) with a
heterozygote (e.g. Aa) with the result that in the offspring the probability is for 50%
expression of each allele. There is no linking among the above characteristics, that
is, they are inherited independently of one another. From such a breeding, over the long
haul, one would expect equal numbers of striped vs. non-striped, black vs. chocolate
pigment, full coat pattern vs. Siamese coat pattern, dense vs. dilute colors, and tipped
vs. non-tipped coats. Also, clearly if one is interested in kittens of a lilac color (bb
dd) there must be chocolate (b) and dilute genes (d) in both parents.
D. To produce chocolate bicolors is relatively straight-forward. Here we have added the (
S) symbol to represent the white spotting gene, which is dominant. and also additive, so
that the cat which is SS tends to have much more white than the cat which is Ss. One could
combine a chocolate CPC (which carries dilute) with a blue and white bi-color. This cross
is represented as follows:
( bb Cc Dd ss X BB CC dd Ss)
The first generation cross between these two cats results in cats of these genotypes:
4/4 Bb black pigment (chocolate carriers)
2/4 Cc full coat color (heterozygous)
2/4 CC full coat color (homozygous)
2/4 Dd dense coat color (heterozygous)
2/4 dd dilute coat color (blue)
2/4 Ss with white spotting
2/4 ss no spotting
The probability is for equal numbers of black and blue, spotted and unspotted cats, and no
Himalayans, since only one of the parents carried the recessive (c) gene. Once again
we need to go to the second generation to see cats of the desired chocolate and lilac
colors. The first cross between the chocolate CPC and the blue and white bicolor yields
the following genetic probabilities:
4/4 Bb All have black pigment (chocolate carriers)
2/4 CC; 2/4 Cc Half carry the Siamese coat pattern gene (c)
2/4 Dd; 2/4 dd Half black, (dilute carriers), half blue (dd)
2/4 Ss; 2/4 ss Half with white spotting, half with none (S)
Since we are aiming at chocolate and lilac bicolors we would select to breed those with
white spotting. Those without white spots do not carry the spotting gene, since (S) is
dominant it shows. We do not know without test-breeding which of these cats carries the
Siamese gene (not desirable in bicolors). Since all of these cats have the chocolate gene,
however, they are potentially useful in breeding other varieties of chocolates if their
type is good. If we are particularly interested in lilac bicolors we would want to select
at least one dilute from this breeding rather than black, to increase the probability of
lilacs. Suppose we select to breed together a black and white bicolor and a blue and white
bicolor from the above breeding. One happens to carry (c), the Siamese gene, and both
carry chocolate:
Bb Cc Dd Ss X Bb CC dd Ss
The probabilities for their offspring would be as follows:
1/4 BB black pigment 3/4 will have black pigment
2/4 Bb black (chocolate carrier)
1/4 bb chocolate 1/4 will be chocolate
2/4 CC full coat color (homozygous) all will have full coat color
2/4 Cc full coat color (colorpoint carriers)
2/4 Dd dense 2/4 will be black or chocolate
2/4 dd dilute 2/4 will be blue or lilac
1/4 SS homozygous for white spotting 1/4 (probable van)
2/4 Ss heterozygous for white spotting 2/4 bicolors
1/4 ss no white spots 1/4 no white spotting
One might wish to breed one of the cats of the above breeding to a visible chocolate or
lilac (bb), since that would double the probability of obtaining chocolate or lilac
kittens:
bb Cc Dd Ss X Bb CC dd Ss
2/4 Bb black 2/4 black (chocolate carriers)
2/4 bb chocolate 2/4 will be chocolate or lilac
2/4 CC full coat color (homozygous) all will have full coat color
2/4 Cc full coat color (colorpoint carriers)
2/4 Dd dense 2/4 will be black or chocolate
2/4 dd dilute 2/4 will be blue or lilac
1/4 SS homozygous for white spotting 1/4 (probable van)
2/4 Ss heterozygous for white spotting 2/4 bicolors
1/4 ss no white spots 1/4 no white spotting
This should keep us busy for a few years!
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