| Coat color inheritance, or genotype, is
the Doberman's genetic potential to produce a particular color. |
| Genotype is indicated by a set
of four letters, each representing a gene. In scientific terms, the
genes represented by capital letters are dominant genes and the lower
case letters represent recessive genes. |
| The first two letters are the
color genes and determine the basic color of the Doberman, either
black (B) or red (b). |
| Each parent contributes one
of their two color genes to their offspring - either a black (B) gene
or a red (b) gene. A (BB) parent can contribute only a (B) gene; a
(bb) parent can contribute only a (b) gene; and a (Bb) parent can
contribute either a (B) or a (b) gene. |
| If a Doberman gets two black
genes (BB) it will be black. If it gets two red genes (bb) it will
be red. BUT if it gets one of each (Bb) it will be black - remember
black (B) is dominant over red (b) - but it has the ability to produce
red by giving the recessive red gene to its offspring. |
| Color can be "modified"
by the second pair of genes. These genes indicate the intensity
of the color and are called the dilution factor genes. Dilution
is a recessive trait. Both recessive genes must be present for the
color of the Doberman to be affected. A (d) indicates the presence
of dilution and (D) indicates the lack of dilution. |
| Blue is the dilution of black
and fawn is the dilution of red. |
| Each parent also contributes
one of their two dilution factor genes to their offspring - either
a dilute (d) gene or a non-dilute (D) gene. Dilute parents (dd)
can contribute only a dilute (d) gene and non-dilute parents (DD)
or (Dd) can contribute either a non-dilute (D) or a dilute (d) gene.
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| Remember the only two color
genes are black (B) or red (b). Both dilution genes need to be present
to affect the color of the dog. A "black" Doberman (BB
or Bb) with both dilution genes present (dd) results in a blue Doberman.
A "red" Doberman (bb) with both dilution genes present
(dd) is a fawn Doberman. Having one dilution gene present (Dd) won't
affect that dog's color, but it will be able to contribute a dilute
gene to its offspring. |
| So far, we've learned that
the color of the Doberman can be either black (BB) or red (bb).
It can also be black with the ability to produce red (Bb) because
black (B) is dominant over red (b). |
| We've also learned that genes
which carry the dilution factor can modify the color genes to produce
the dilute colors of blue and fawn. Both recessive dilute factor
genes must be present to affect the color of the dog. Both dilution
genes (dd) in a black (BB or Bb) produces blue and both dilution
genes (dd) in a red (bb) produces fawn. If only one of the dilute
(d) genes is present, it won't affect the color of the dog, but
it can be passed on to its offspring. |
| So how do we get Albinos? |
| The Albino gene, also called
a "masking gene", is totally unrelated to the color (BB,
bb, or Bb) genes or the dilution (DD, dd or Dd) genes that we discussed
earlier. |
| Albino Dobermans came about
because of a mutation in the gene for tyrosinase, an enzyme catalyst
that helps in the conversion of tyrosine to the pigment melanin.
This mutated recessive gene, called (c), greatly reduces the number
of pigment granules in hair, skin and eyes, giving these Dobermans
the appearance of a light cream based coat with white markings and
translucent blue eyes and pink noses, eye rims, and foot pads. |
| This gene hides ("masks")
the true color and intensity of the dog, which still has copies
of genes for both color and dilution that we already discussed.
An Albino is produced only if both recessive copies (cc) of the
gene are present - one from each parent. |
| A Doberman with the gene pair
(Cc) is of normal color but is able to produce an Albino if it contributes
the recessive (c) gene to its offspring. This normal colored Doberman
is referred to as "white-factored". |
| This (c) gene is not related
to, and does not interfere with the four acceptable colors of the
Doberman and it does not need to be included in the genotype color
discussion below. |
| There are nine basic genotypes in the Doberman,
representing the various combinations of color and dilution genes.
Mr. W. Donald Thompson arranged a chart, still in use by the DPCA,
to indicate expected outcomes from breeding together dogs with the
different color and dilution gene combinations. Mr. Thompson assigned
a number from 1 to 9 to each of these combinations on the DPCA
Color Inheritance Chart. |
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1 |
BBDD |
#1 is a
black Doberman (BB) who can only produce black offspring because
it only has non-dilute factor (DD) genes. Its genotype is (BBDD)
and is referred to as a "#1 Black". |
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2 |
BBDd |
#2 is a
black Doberman (BB) who carries the dilute gene (Dd). It can produce
black offspring if it contributes the non-dilute factor (D) gene
or blue offspring if it contributes the dilute factor (d) gene.
Its genotype is (BBDd) and is known as a "#2 Black". |
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3 |
BbDD |
#3 is a
black Doberman who can produce red offspring (Bb) and does not carry
the dilution factor gene (DD). It produces black by contributing
the dominant black gene (B) and red by contributing the recessive
red (b) gene but has no dilution factor genes to produce blues or
fawns. Its genotype is (BbDD) and is known as a "#3 Black". |
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4 |
BbDd |
#4 is a
black Doberman who can produce red offspring (Bb) and can also contribute
the dilute (Dd) gene. This dog can produce all four colors depending
on which color genes - black (B) or red (b) - and which dilute factor
genes Ð dilute (d) or non-dilute (D) - are contributed and in what
combination. Its genotype is (BbDd) and is known as a "#4 Black".
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5 |
BBdd |
#5 is a
blue Doberman (dd) whose color genotype is black (BB). Remember
you need two dilute factor genes (dd) to get dilution. This dog
can only produce blue or black. This dog can contribute only the
black (B) color gene and can contribute only a dilute factor gene
(d). Its genotype is (BBdd) and is known as a "#5 Blue".
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6 |
Bbdd |
#6 is a
blue Doberman (dd) who can produce red offspring (Bb). This dog
can produce all four colors much like the #4, depending on which
color and dilute genes are contributed by each parent. Its genotype
is (Bbdd) and is known as a "#6 Blue". |
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7 |
bbDD |
#7 is a
red Doberman (bb) that does not produce dilution (DD). This dog
can produce reds and blacks by contributing a red (b) color gene
but no dilution as it only has non-dilute factor (D) genes. Its
genotype is (bbDD) and is known as a "#7 Red". |
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8 |
bbDd |
#8 is a
red Doberman (bb) that can produce dilution (Dd). This dog can produce
all four colors depending on the combination of color and dilute
genes given by each parent. It can only give a red (b) color gene
but contribute either a dilute (d) or non-dilute (D) gene. Its genotype
is (bbDd) and is known as a "#8 Red". |
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9 |
bbdd |
#9 is a
fawn Doberman who's color genes are red (bb) with both dilute genes
(dd) to make it fawn, the dilute of red. This dog can produce all
four colors also. A fawn dog always contributes a red (b) color
gene and a dilute (d) gene. Its genotype is (bbdd) and is known
as "fawn" (or Isabella) since this is the only genotype
combination that a fawn Doberman can have. |
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| In summary, every Doberman
has a pair of color genes and a pair of dilution factor genes. Every
parent contributes one of each to its offspring to determine that
dogs color. Without genetic testing, we can only know the color and
dilution genotype of the parent by breeding and knowing what color
puppies the dog has produced in multiple offspring. If we know the
parent's genotype, the color of the resulting offspring can be predicted
with some accuracy. It's important to remember that "predicted"
and "actual" aren't always the same. Just as you can "predict"
the probability of half males and half females in a litter, in "actuality"
this rarely happens. It's the same with color inheritance. |
