06/07/2022
Dobermann Coat Color Genetics by
Cathy Kendrick:
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.
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.
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".
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".
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".
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 � dilute (d) or non-dilute (D) - are contributed and in what combination. Its genotype is (BbDd) and is known as a " #4 Black".
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".
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".
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".
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".
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.
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.
