Progeny inherit genes for both desirable and undesirable traits from both parents. Breeders
conserve desired characteristics and suppress undesirable ones by repeatedly selecting
meritorious individuals from each generation to be the parents of the next. This process
leads to a population expressing a combination of inherited traits that distinguishes
it from the rest of the species.
~The Columbia Encyclopedia, Sixth Edition. 2001.

Coat Color Inheritance
Marking Pattern Inheritance

There are two coat colors in Boxers, fawn and brindle. Fawn ranges from pale tan to dark deer-red (mahogany). Brindle is actually a stiping pattern, not a color - all brindle dogs have a fawn ground color. Brindling is influenced by what are called "modifiers", so the black stripes of a brindle can be sparse (but clearly defined) to so heavy that the fawn ground color barely shows through. The latter are often called "reverse", "seal", or "black" brindles. It is important to point out, however, that "black" brindles are still brindles - the Boxer does not carry the gene for a black coat color. There are those who try to sell their "rare black" Boxers - however every one of these dogs that we have run across either does have some fawn on it, or is very obviously not a purebred Boxer.

The goal here is not to get into a thorough discussion of genetics. Sue Ann Bowling has written excellent articles on canine coat color genetics, basic genetics, and several other topics relevant to dog breeding.

Every Boxer carries two coat color genes, inheriting one from each of its parents. There are two different genes for coat color - fawn and brindle.

Fawn Gene b	Brindle Gene B

The number of each gene a Boxer gets determines its coat color. The brindle gene is dominant, which means that any time a dog has even one brindle gene, it will be a brindle.

Fawn Dog (bb)

Double Brindle Dog (BB)

Single Brindle Dog (Bb)

Below are the different genetic combinations that can occur in Boxers. Note that a brindle dog that carries only one brindle gene can produce fawn puppies, if it is paired with a dog that carries at least one fawn gene. (Phenotypically refers to the way the puppy looks - the coat color that you see.)

Another important note: While the actual distribution of genes in an individual litter may stray from the expected (i.e., a fawn x single brindle breeding may produce 100% fawn puppies), over a large number of litters the numbers will meet the expectations.

Fawn x Fawn (bb x bb) 100% Fawn Phenotypically 100% Fawn

Fawn x Double Brindle (bb x BB) 100% Single Brindle Phenotypically 100% Brindle

Note here that a fawn x fawn breeding can only produce fawn puppies. There seems to be some confusion on this, with people thinking that if the grandparents were brindle the puppies could be brindle. As is shown in the example on the left, the only possible genetic combination resulting from a cross of two fawn parents is a fawn puppy.

Fawn x Single Brindle (bb x Bb) 50% Fawn (bb) - 50% Single Brindle (Bb) Phenotypically 50% Fawn, 50% Brindle

Single Brindle x Single Brindle (Bb x Bb) 25% Fawn (bb) - 50% Single Brindle (Bb) - 25% Double Brindle (BB) Phenotypically 25% Fawn, 75% Brindle

The single brindle dogs will look exactly the same as the double brindle dogs. There is sometimes the misconception that dogs with two brindle genes are the darker brindes - this is not true, and there are many very dark brindles that have produced fawn puppies (meaning, again, that they must carry one fawn gene).

Single Brindle x Double Brindle (Bb x BB) 50% Single Brindle (Bb) - 50% Double Brindle (BB) Phenotypically 100% Brindle

Double Brindle x Double Brindle (BB x BB) 100% Double Brindle Phenotypically 100% Brindle

Again, single brindles will look the same as double brindles. The only way to know with certainty that a dog is a single brindle is if it produces a fawn puppy. The fact that you breed it with a fawn and it does not produce a fawn puppy means nothing - it may just not have "sent" a fawn gene to that litter. You will never know for certain if a dog is a double brindle. However, if you breed it to a fawn or to another brindle, and a fawn puppy is born, you know for a fact that the dog is a single brindle.

Coat Color Inheritance
Marking Pattern Inheritance
Now we get into the issue of marking patterns. There are three marking patterns in Boxers - solid colored or "plain", marked or "flashy", and "check" or white. Again, there are only two genes responsible for marking patterns, the solid color gene and the marking pattern gene (often called the "white" gene).

Gene for Solid Color S

Gene for White Markings Sw

The number of each gene a Boxer gets determines its marking pattern. Neither gene is dominant over the other, which means that in a dog that has one of each gene you will see a "combination" effect; in this case, a flashy Boxer.

It is important to note a few things here. One is that, like brindling, the marking pattern is affected by modifiers, so that a flashy Boxers, while genetically the same as another flashy Boxer, will not be phenotypically the same - one may have a full white collar, the other may only have white "stockings" and no white on the neck. Also, genetically plain Boxers do have a minimal amount of white markings on the toes, chest and belly. Because of the modifiers, a genetically flashy Boxer that is modified to have only a small amount of white markings may look phenotypically identical to a genetically plain Boxer. Finally, because white is a marking pattern and not a coat color, a white Boxer is always either fawn or brindle. If the white covers the entire body, you may never know which color it is (unless it happened to come from two fawn parents).

Two Solid Color Genes (SS)

Two White Markings Genes (SwSw)

One of Each Gene (SSw)

Below are the different genetic combinations for marking pattern that can occur in Boxers. (Again, phenotypically refers to the way the puppy looks - the marking pattern that you see.)

Plain x Plain (SS x SS) 100% Plain (SS)

Plain x White (SS x SwSw) 100% Flashy (SSw)

It is interesting to note that a white x plain breeding will produce 100% flashy puppies, which are so desirable in the show ring.

Plain x Flashy (SS x SSw) 50% Plain (SS) - 50% Flashy (SSw)

Flashy x Flashy (SSw x SSw) 25% Plain (SS) - 50% Flashy (SSw) - 25% White (SwSw)

Including a genetically plain Boxer in any breeding pair will guarantee that white puppies are not produced. It would seem that those breeders who still feel that whites should be avoided at all costs would take this simple step; sadly that is not often the case. To be fair, it is impossible to know with certainty if a dog is genetically plain, but using dogs with very little white markings would at least be less hypocritical.

Flashy x White (SSw x SwSw) 50% Flashy (SSw) - 50% White(SwSw)

White x White (SwSw x SwSw) 100% White (SwSw)

There have been some accounts of a white x white breeding producing colored puppies. If this is the case, the genetics of white Boxers will need to be re-examined; quite possibly the piebald gene, which is thought to not be present in the breed, is found in some populations. However, we have only heard of this occurrence through the "grapevine" as it were, and so cannot lend personal credence to the theory at this time. Our friend, Theresa Garton of Winmere Boxers, has a brief discussion of her theory on this topic here.