Breeder's Digest Dog Blog

23/07/2020

It has been some time since I wrote a post on here and I am truly sorry for the massive break.

With that being said I have been doing a lot of research on Studs.

One thing I see a lot of purebred breeders doing is offering their studs to just about everyone who needs or wants one. You might ask, "What's the problem with studding out your stud? Isn't that his purpose?" Yes and no.

You see I have a stud and he is a great looking boy. He has nice structure, amazing temperament, the dogs in his pedigree are also fantastic and on top of it his color is stunning. Yes he flaws and he isn't perfect but he is very well put together. Now if I let anyone and everyone use my stud, purebred or not, that not only makes me irresponsible but I'm giving me and his breeder a bad name. If you purchase a dog from a breeder you will forever be attached to their name.

You also have to ask "What is this breeding doing for my breed?"
Does it make the breed better in any way? Does the stud compliment the female? Are they sound in structure, temperament and health?

These are just a few basic questions you should ask yourself with every breeding, not just when looking for your dogs next boy/girlfriend but in your own yard as well. There are dogs out there that I just LOVE but if they don't help me out with what I'm trying to "fix" or do with my dogs and program then what really is the point of using them?

Another thing people do A LOT is breed to "the next big thing". Everyone wants the big name dog in their pedigree no matter if he/she add good qualities to their dog. I see this mostly in my breed. But when it comes to color i see this in just about every breed. Now there really isn't anything "wrong" with the dog's coat color, although some can become dangerous, like merle or high white content dogs (See my posts on Coat Color Genetics). I see merle dogs in my breed (American Bully), I see blues and chocolates in German Shepherd Dogs, I see Silvers in Labradors and the list goes on. Like I stated before there really isn't anything "wrong" with the color but if it is a fault or disqualification in the breed standard then it's not longer that breed. You cannot breed purebred dogs and change the breed standard. That's just not how it works.

So when you're either looking for a stud or someone wants to use your stud, ask yourself those questions. Don't sell yourself, your dog or his breeder short by just throwing him out there for anyone and everyone to use. Know his worth, set him and yourself up for success and make sure you are always trying to make each breeding just a little bit better then the one before.

22/07/2020

I'm a research person and Im always trying to learn new things so I'm always reading books and blogs, listening to podcasts and watching YouTube videos to learn.

Something that has really stuck out to me this week was a breeder said "if you are intentionally breeding a dog outside of the standard it's not longer that breed". I feel like that rings so true to the American Bully breed.

I watch...a lot...and I see so many people breeding outside the standard. Usually their excuse is "it's a young breed so the standard isn't really set". But that's the thing, if it wasnt set then it wouldn't be a breed. The standard is there for a reason. It's not just take what you want out of it and use that but not this part over here.

Another breeder said that when her breed's standard was written there were a lot of things that the writers didnt add, but as the breed became more popular people started doing what they thought the standard should be. Because of this, the standard has to be revised to state that these specific things were faults.

Obviously no dog is perfect but as breeders and dog people we should always be trying to reach that goal of as close as possible to the standard. And intentionally breeding dogs outside of it seems like we are taking steps backwards not forward.

Just my thoughts today. Feel free to add your thoughts as well. Thanks for reading.

29/04/2020

My computer crashed so I cannot finish my next post 😭 It will be postponed until my computer is fixed or until I get a new one

23/04/2020

I have been working on a new post but it's been taking longer then I wanted. Hope to have it published soon!

12/03/2020

12/03/2020

Color Genetics
Part 3
Part three of our coat color genetics. In the first two parts we covered the two types of pigments, eumelanian and phaeomelanin, and several of the genes responsible for coat color.
A quick recap:
A loci is responsible for sable, agouti, tan points, saddle/creeping tan and recessive black.
K loci are responsible for dominate black and brindle. in this section we also gave the known info of seal and ghost tan.
B loci are responsible for brown, also known as liver and chocolate.
D loci are responsible for dilute colors blue and isabella, also known as grey and lilac.
E loci are responsible for masks, recessive red, grizzle and domino.
G loci are responsible for graying in dogs like the Kerry Blue Terrier, not to be confused with the dilute color blue/grey.
M (Merle)
Merle is one of the most unique and beautiful color patterns. No two Merle are the same and are a fascinating color. Merle is dominate so, as you should know by now, it only take one M allele for a dog to be Merle. Merle is interesting in the fact that all normal Merle are heterozygous(M/m). Heterozygous means a gene pair that are different i.e. M/m. A homozygous Merle (a gene pair that are the same i.e M/M) is a double Merle. I will talk more about them later.
The Merle gene dilutes random patches of coat to light colors, usually grey in black dogs and isabella in liver dogs, leaving patches of the original color remaining. These patches can be any size and located anywhere on a dog. the edges can be jagged or look torn.
Merle only affects eumelanin, which means that only black, liver, blue, and isabella in the coat, eyes, or nose will be merled, whether its the whole body, a mask on sable, shading, brindle pattern or even a saddle. Phaeomelanin is not affected and will appear normal.
Merle dogs can come with a number of health problems like blindness and deafness, sun sensitivity and skin cancer. These problems are unusual in normal heterozygous Merle (m/m) but are very common in double Merle. For this reason it is the reason two Merle dogs should never be bred together as this will result in double Merle puppies. The reason Merle can be problematic is it can cause lack of pigment in vital areas like the eyes and inner ears. Most normal Merle dogs have plenty of pigment because they will have the non-Merle allele to help make it. Double Merle do no have this allele and often have large white areas where their is no pigment produced at all.
Because Merle can affect both the nose and they eyes you may see dogs with all or partly pink noses, often referred to as butterfly noses. Some Merle dogs will have all or partly blue eyes. Not all meres have blue eyes or pink noses and meres with heavy dark patching are more likely to have normal eye and nose pigment.
Merle dogs can have a large range of patterns on their coats. Some have very minimal black or liver patches, some have a mix of large and small patches that cover about 50% of the body. This pattern is generally the most preferred in breed standards. Some dogs have very large color patches, sometimes referred to as blanketing, while others, known as minimal Merle are almost completely black or liver with very minimal amount of Merle. Dogs with little to no visible Merle are often called cryptic Merle.
Cryptic Merle is just one example of how the Merle gene can be "hidden". Cryptic Merle has little, if any, visible Merle because their patching is so heavy. One other way Merle can be hidden is through recessive red. These recessive red dogs are unable to produce any eumelanin pigment in their coats, making them solid red. (See part 2 for more on recessive red) Sometimes a recessive red Merle will have blue eyes or partially blue eyes, but otherwise just appear to be normal red. Sometimes these dogs are called phantom Merle.
Recessive red and Merle can be a very dangerous combination because you may not know that a recessive red dog is actually Merle as well. these two genes, recessive red and Merle, occur together in a number of breeds like Chihuahua and Border Collie. Clear sables cab also "hide" Merle almost as effectively as recessive red. Sometimes Merle can be hidden by long or wire coats but the Merle should be visible enough at birth or when the dog is shaved down,
Double Merle are typically mostly white and may have Merle patches on the head and sometimes the body. On double Merle, both the eumelanin and phaeomelanin pigments are affected. The M/M genotype causes loss of pigment to such an extent that it tends to remain only on the upper areas of the dogs like the top of the head, the back, and base of the tail. Sometimes double Merle are even more completely white. The nose is mostly pink or all pink and the eyes are generally wall or blue. Wall eyes are known as heterochromia, and are when a dog has one blue eye and one brown or amber eye.
Tweed is a Merle modifier that turns the diluted parts of the coat that or normally grey/blue or light born/isabella, into a variety of brown, grey and tan hairs. Tweed is most commonly seen is Australian Shepherds and Catahoula Leopard dogs and is known as patchwork. Tweed is often assigned it own locus, Tw and is thought to be dominate.
H (harlequin)
Harlequin occurs in its own locus, H. It is dominate so only one gene is needed to be harlequin. It is inherited separately to Merle.
Harlequin is also a Merle modifier and it turns the areas between the dark patches on a Merle into pure white, with the occasional grey ticking or patches. This means a blue (black) Merle will become white with black patches because all the blue (grey) it the coat is turned to white. This gene also affects phaeomelanin. This means that a sable dog with the Merle gene wont just be affected on the parts of its coat that are black (masks, tipping) but the whole of the coat will be harlequin. this has become known as fawnequin, tan patches on a white base with black patches.
Every dog with the harlequin gene and the Merle gene will display harlequin. The only other genes that would stop harlequin from being visible would be ones that turn a dog completely or almost completely white and these are not present in the Great Dane, except double Merle. The harlequin gene requires the Merle gene to work. It is thought that harlequin is an embryonic lethal gene, meaning that two copies of it will cause a puppy to be re-absorbed into the womb. This means that we can assume all harlequins are heterozyhous for harlequin and it is true that all harlequins that have undergone genetic testing so far have been heterozygous. a very lightly marked harlequin with very few spots may be homozygous for Merle, or double Merle. A non-harlequin dog may carry harlequin but not display it (lack of Merle gene) and if bred to a Merle may produce harlequin puppies.
S (no white, piebald, extreme white, Irish spotting)
These areas of the dog are the white areas and can occur on any color or pattern and the technical term for it is epistasis. The white hair occurs when the skin cells are unable to produce any pigment. Nails and paw pads may also become pink in white areas where pigment is not produced.
So far there are only two proven white alleles. There is a third that may be responsible for extreme white but has not been proven yet.
sp (piebald)
Piebalds usually produce a dog with a colored head, with or without white on the muzzle and/or blaze, and colored patches on the body. Many times the base of the tail will also be colored and very rarely will the legs be colored. Body patches are random.
Piebald is a recessive gene and heterozygotes (piebald carriers) don't always have any white markings. Because of this, piebald can remain hidden and pop up unexpectedly.
sw (extreme white)
Extreme white is a dog with very minimal to no color patches, usually on the base of the tail and/or on the head. If they have body patches they are normally small.
So far all extreme white dogs that have been tested have shown to be homozygous for the piebald gene (sp/sp) just like a normal piebald. However there is a big difference between and normal piebald and an extreme white dog. It is possible there is something that is causing the high white. It may be simply caused by the interaction of the Irish spotting and the homozygous piebald you see in breeds that carry both like the Bull Terrier and Greyhound. In other breeds the cause is less obvious and has led some people to postulate a further S allele (aw). There is, however, no evidence found for its existence of the aw allele.
Extreme white can occasionally cause problems because it removes large color amounts of pigment from the face and ears. Lack of pigment in the inner ear can cause deafness. Dogs with exposed un-pigmented skin, or pink skin, are also more prone to skin cancer that those with more pigment.
si (Irish spotting)
Irish spotting in the pattern known as mantle or tuxedo, sometimes as Boston. These terms to not always refer to true Irish spotting. A dog with Irish spotting, white is found on the legs, chest, neck, muzzle and tip of the tail. Many dogs with this pattern have a full white collar and and face blaze.
It is as of yet an unidentified gen that causes true Irish spotting, but we can assume dogs to be homozyous for it (si/si) as it breeds true. This means that two dogs bred together that are Irish spotted will produce puppies with Irish spotting.
Pseudo-Irish
Pseudo Irish spotting may look like some or very similar to true Irish spotting but it is not caused by si/si but by S/si. In other words these dogs are actually heterozyous or even potentially homozygous piebalds. The incomplete dominance of S means that an S/sp dog may show up as half the white of a sp/sp dog. These dogs do not breed true so when two are bred together puppies may be solid, piebald or in between. Some that are true Irish spotted will not usually have white on the hip/knees or the underside of the body so this is a good clue that sp is present.
A "flashy" Irish spotted dog is one with more white than usual and may be caused by the combination of si and sp. This has been known to happen in breeds like the Shetland Sheepdog who carries both Irish spotting and piebald. These dogs have more white around the neck and underside of the body.
Split Faces and White Heads
This is thought to be a separate gene or a modifier that causes some Irish spotted, piebald or trimmed dogs to have a split or completely white face. Split and white faces are common in bull breeds and the cause is unknown

12/03/2020

Color Genetics
Part 2
This is the second part to the basic of color genetics. In part one we explained how there are 2 types of pigment. Eumelanin, the default color is black, and Phaeomelanin, the default color is red.
We also covered two of the ten loci, A and K. A alleles include sable, agouti, tan points, and recessive black as well as the modifiers saddle and creeping tan. K alleles include dominate black and brindle as well as what is known of seal and ghost tan.

B (liver, chocolate, brown)
Liver is recessive to black and a dog needs to have the genotype of b/b to be liver. A liver puppy can be born to two black parents if both parents are carriers of the liver allele. Liver dogs are not dilute but can be affected by dilute on the D locus.
Liver is simply a different color of eumelanin and therefore everything that would normally be black on a black dog will be turned to brown like the coat, nose pigment and eye rims and the eyes will be amber or light brown. Sometimes the nose will be pinkish.
It is genetically impossible for a liver dog to have a black or grey hair in its coat, the same goes for black or blue dog cannot have a liver hair in its coat. However, a liver dog may have some red or phaeomelanin hairs depending on the K and A locus alleles present.
Liver goes by many different names depending on the breed. In some its called chocolate, others its known as red or brown. Liver Merle are commonly called red Merle. The best and usually the most reliable way to tell a liver dog from a black or blue is the nose color. Sometimes dogs are born with only phaeomelanin in their coats, like sables or recessive reds, but these dogs will still have one of the eumelanin pigment colors-black, blue, liver or isabella. Every dog can be said to be genetically black, blue, liver or isabella, whether they have pigments colors or not in their coats. This color is generally noticeable in the nose. For dogs with pink noses you will look at the eyes instead of the nose.
D (dilute blue and isabella)
Dilute is also a recessive gene. For a dog to be dilute he must carry the genotype of d/d. Dilute affects eumelanin, although phaeomelanin may be lightened. When a dog carries two copies for dilute, the dog will either become blue or isabella. Blue is a dilute of black and isabella is a dilute of liver. Blue is also known as slate and isabella is also known as lilac. Blue and isabella can have any coat pattern but anything that is black or liver will be blur or isabella.
Dilute also affects nose color so a dog may be sable or recessive red, but if the nose is blue, then it is genetically blue-pigmented. Isabella is a bit trickier. Both liver and isabella can have very light or even pink noses and its common for isabella dogs to have darker noses like a liver dog.
Dilute also causes eyes to lighten to amber. Its usually more pale than the amber eyes on a liver dog.
E (masks, recessive red, grizzle and domino)
E stands for extension and is responsible for almost all non-A locus related patterning. Em-masked, Eg and Eh-grizzle/domino, E-normal extension, and e-recessive red.
E (normal extension)
Normal extension has no effect on the phenotype.
Em (masks)
Em or the mask allele is the top dominate gene on the E locus, which means a dog only needs one allele to have a mask. Masks are made up of eumelanin pigment so the colors can be black, blue, liver or isabella and even Merle. Masks can also appear on any dog that is genetically sable, tan point, saddle or agouti. The expression of the mask depends on both the A and K loci. If a dog is dominate black he cannot express what is on the A locus so a dog will have to have the genotype of kbr/kbr, kbr/k or k/k. If a dog is brindle or non-solid black they can express the A locus, so any dog that is sable, tan point, saddled or agouti can all show masks. Recessive black will not be visible because the dog is solid black.
On a tan point dog, masks are only detected when a mask covers the facial marking. Masks vary from just the end of the muzzle or can go all the way up to the eyebrows and ears. Many sable dogs, like pugs and Great Danes have masks. The black masks may also cause black hairs on the chest and /or the back and tail.
In a small amount of breeds, masked dogs have a large amount of shading to the chest and legs, like we often see in the Belgian Malinois. The shading occurs on the under side of the dog and it is unknown what causes this. There is a possible connecting between this shading and "etching". Etching is when a sable piebald or Irish spotted dog appears to have a border around each color patch. Its commonly seen in Akita's and St. Bernard's, both also have heavy masking.
e (recessive red)
Recessive red is probably one of the most fascinating genes and also probably the most dangerous. Although recessive on the E locus, it is essentially dominate over almost all the other loci. Dominate black, sable, tan point, agouti, Merle and any other pattern with black(or whatever the eumelanin pigment color is) will be turned to solid red because of the recessive red gene. The nose, eye rims and lips will remain the eumelanin color. It is impossible to know what a recessive red dog carries just by looking at it as will it be impossible to know what is passes on to its offspring unless tested.
Recessive red occurs in few breeds, but many of those breeds also carry sable. Clear, unmasked sable can look identical to recessive red. Golden Retrievers and Labradors are known to carry only recessive red(not clear sable). Breeds like the Dachshund and Pomeranian carry both.
It is common for the pigment on the nose, eye rims, lips and nails to fade even though the recessive red allele does not directly affect the color. The pigment is often faded from black to grey or pink as the dog ages. Liver recessive red dogs usually show more significant pigment loss than black dogs.
Eg and Eh (grizzle and domino)
Grizzle looks very much like shaded sable or creeping tan and is only found in Saluki, where it is called grizzle, Afghan Hounds, where it is called domino, and in Borzoi, where it is called sable. The shaded color varied from black/grey to brown.
Grizzle is dominate over all other E locus allele other than Em. This means that a grizzle dog can never have a mask. Grizzle can only occur on dogs that have the tan point allele on the a locus, so a dog must have both the tan point allele as well as the grizzle allele to be grizzle. A dog with a grizzle allele and no tan point allele will not be grizzle and will just express the A locus normally. This means that breeds like the Greyhound may carry grizzle but never express it because they do not carry the tan point allele.
The grizzle allele(Eg) is thought to be a modifier of the tan point gene.
Eh is an allele discovered in English Cocker Spaniels and is known as sable. Eh is almost identical to Eg and is a modifier of the tan point gene. All cocker spaniels are "fixed" for tan points, meaning they are all at/at but only some carry Eg.
There is one important way in which Eh is different from Eg. While all grizzle Saluki's tested so far have been k/k on the K locus, all sable cockers tested so far have been K/k or K/K. k/k cockers with the Eh allele have been reported as "dirty red", not sable. This suggests that Eg works differently than Eg as it appears to override dominate black.
G (graying)
Graying is thought to be dominate so a dog only needs one G allele to express it. graying only occurs is a few breeds and is expressed only on dogs with long, curly, or wire coats. Short haired dogs may have the gene but do not express it.
Graying only affects eumalanin and does not normally affect the nose or eye color. Graying is progressive so a dog may be born black and lighten as they age and it does not always affect the whole coat to the same extent. It is rare for the graying gene and the dilute gene to occur in the same breed.
Graying does not affect phaeimelanin to the same extent. Sometimes breed that carry both the graying gene also come in shades of cream. This suggests that lightening of the two types of pigment is connected.
While graying affects dogs with tan markings like tan point, saddles and so on, it does not affect masks. Kerry Blue Terriers have a silvery coat while their muzzles remain solid black. It is unknown why this happens.

12/03/2020

Color Genetics
Part 1

One of the first things we notice and usually the first thing we fall in love with about our dogs is their coat color. And just about everyone has a favorite color in their breed. I personally love the chocolate coat color, also known as liver in other breeds. But no matter what the name for the color is, there is much more to color than meets they eye.
An important reason to know at least the base of color genetics is to breed safely. There are some color or patterns that should never be bred together and some that are known to have health issues associated with them.
In this and the next few posts, I will go over the base of color genetics that I believe every breeder should know. I will try to keep it simple and try to include as many pictures as I can. So please bare with me as I am still learning.

There are 2 types of pigment, Eumelanin and Phaeomelanin. The pigment is what gives the hair its color. All coat colors and patterns are created with these 2 pigments and each has a "default" color that can be modified by various genes.
Eumelanin
This pigment's default color is black. There are genes that turn eumelanin into other colors-liver(chocolate), blue(grey) or isabella(also known as lilac in some breeds). If the dog has any of the genes that turn black pigment into liver, blue or isabella. Eumelanin is also present in other areas that needs pigment like the eyes and nose. Only Eumelanin can affect the nose and eyes.
So the default color of eumelanin is black but it can be turned into liver. Black and liver can be diluted to be blue and isabella.
Phaeomelanin
This pigments default is red. "Red" covers everything from a light cream to a deep red like in an Irish setter. Phaeomelanin is only produced in the coat, not the eyes or nose.
The following are the loci associated with color
A (agouti)
K (dominate black)
B (brown)
D (dilute)
E (extension)
M (Merle)
H (harlequin)
S (spotting)
T (ticking and roaning)
G (graying)

A(sable, agouti/wolf grey, tan points, saddles/creeping tan, recessive black)
The agouti or A loci has 4 known alleles: ay-sable, aw-agouti or wolf grey, at-tan points, and a-recessive black. This loci controls the cells that produce eumelanin. The A loci can only be expressed if the dog has one of the following genotpyes on the K locus: k/k, k/kbr or kbr/kbr. k/kbr and kbr/kbr will add brindle on top of any phaeomelanin areas. If the dog has just one K allele then it will be solid black, liver, blue or isabella depending what is carried on the D locus. A dominate black dog(carrying one K allele) may genetically be sable, tan point or agouti but will not express it.
Lets look a little deeper....
Ay-Sable
Ay, or sable is the most dominate in the A loci, so being the most dominate a dog only needs one sable(ay) allele to express it. There are 3 types of "patterns" that can modify sable (which has yet to be identified as of yet), clear sable, tipped sable, and shaded sable.
Clear sable are completely red dogs. They can be almost impossible to distinguish from recessive red dogs unless they have a mask, which never appears on recessive red dogs. If there is any black, liver, blue or isabella in the coat at all the must be sable rather than recessive red. (recessive red dogs cannot produce any eumelanin). Clear sable is most commonly known as fawn.
Tipped sable are red dogs with black, liver, blue or isabella hairs. They usually have these hairs on their back, head, tail and ears. Most tipped sables have a mask.
Shaded sables overlap the tipped sables and red dogs with brown and black hairs covering the top of the head, ears, and back. The shading can be very light to vary dark and they have "widow's peak" on the forehead where the dark hair forms a point, kind of like Micky mouse. Shaded sables can also be blue, liver and isabella. In some breeds shaded sables are known as S**t.
aw-agouti/wolf grey
Agouti is mostly seen in the breeds that are closely related to the wolves as well as some northern breeds. In its normal form, agouti can look almost identical to shaded sable. The difference is banded hairs. Banded hairs means the fur is growing, first the cells produce the pigment and then they switch to another type, usually phaeomelanin. The gene then tells the cells to switch back to the pigment. So you end up with a hair the for example is black then white then black again. Agouti also tends to follow the same pattern as tan points with a nose bar instead of widows peak.
When combined with phaeomelanin dilution, agouti becomes much more distinctive as the red hairs then become cream to grayish.
Another thing to remember is when a German Shepherd is called sable, they are actually agouti.
at-tan points
Tan points are at the bottom of the recessive A loci. This means that a dog must have 2 copies of the tan point gene to express it. Tan point is one of the most well known marking and they appear above the eyes, sides on the muzzle and extend to the cheeks, pips on the cheeks, the front of the chest, on the lower legs and feet and the insides of the legs and a patch under the tail. Most commonly known to be paired with black but can also be paired with liver, blue and isabella. Black markings on the toes is called penciling.
Sometimes tan points can be covered up by a mask, depending on how far that masks extends, you my still be able to see the tan points above the eyes.
The saddle pattern and creeping tan are thought to modifiers of the tan point gene, although the modifier has yet to be located. The saddle and creeping tan modifiers causes the eumelanin on the dog to "retreat" to the dogs back only leaving the rest of the coat "tan". A dog with creeping tan is slightly more red or tan than normal tan pointed dogs. The saddle pattern is the next step after creeping tan and the red/tan extends over the whole head, the front of the neck and chest and the top of the legs, only leaving the black (or other eumelanin color) on the back, back of the neck and tail.
Saddle and creeping tan dogs are usually born black and tan (or any other eumelanin) and the black recedes as the dog grows. These patterns are most commonly seen in hounds, terriers, and German Shepherd Dogs.
a-recessive black
Recessive black is a rare gene and only occurs in a handful of breeds like German Shepherd Dog, Shetland Sheepdog, Puli and Samoyed. These dogs are unable to make any phaeomelanin pigment. A dog needs 2 recessive black genes to be recessive black. The only difference in dominate black and recessive black are in breeding. A solid black puppy maybe born from parents who are non-solid black if they both carry 1 copy of the recessive black gene(they will not express it). A dominate black puppy can only be born if one or both parents are also dominate black. The recessive black gene is on a different locus as the dominate black gene, making it the only way that a dog can still be born solid black if it is kk(non-solid black) on the K locus. Both recessive black and dominate black look the same.
Something to note is that above I stated that Samoyed are recessive black, but the dog appears white. This is because here, it is combined with other alleles, which dilute or remove the pigment.

K(dominate black, brindle, seal,"ghost" tan)
There are 2 basic markings for dogs, solid-no red/ tan markings or non-solid-red /tan marking of any sort. Whether a dog is solid or non-solid depends entirely on the K locus. K has 3 alleles:K-dominate black, sometimes referred to as KB, kbr-brindle, and k-recessive non-black.
K-dominate black
Because K is dominate black a dog only needs one K allele and they will be solid black. This color can be changed to liver, blue or isabella or even Merle. Any dog with even one K allele will not be able to express anything on the A locus. For example, a dog may be genetically sable or tan point but because it is K/k or K/K on the K locus this dog will look solid black (or liver, blue, isabella or Merle). The only way for phaeomelanin(red) can be added to the coat of dominate black gene dog is through the E locus(recessive red). This will turn dominate black dogs(or any dog) into a solid red dog with a black pigment. A great example of a dominate black dog is the black lab. They have no red coloring in their coat. A chocolate lab is also dominate black only this dog carries the liver gene so his coat is brown. A yellow lab is also dominate black but carries recessive red which changes his coat color. A yellow lab with a brown nose also carries the liver gene and if he did not carry recessive red, he too would be a chocolate lab.
kbr-brindle

A dog with 1 or 2 kbr alleles will express whichever allele is on the A locus, but all phaeomelanin or red in the coat will be brindle. So for example, a solid brindle dog will be ay/ay on the A locus. A dog with brindle points will be at/at on the A locus, this is commonly known as trindle. These dogs will only have the brindle expressed on the tan points because brindle can only affect the red coloring.
Brindle usually appears as black stripes on a red base. The stripes are eumalanin and the base is phaeomelanin. Eumalanin can be affected by Merle, harlequin, liver, dilute, graying and recessive red, so those pigments can be changes to any of those genes. Phaeomelanin can be affected by intensity locus, making the base lighter or darker. Any white or ticking can also occur on any brindle dog as well.
Liver and dilute can also affect brindle. A dog that is b/b on the B locus will have brown stripes. A dog that is d/d on the D locus will have blue stripes and a dog who is both d/d and b/b with have isabella stripes.
Since both brindle and Merle only affect the eumalanin areas or a dog, any brindle that appears to be broken up into shorter stripes and spots may be a Merle.

Seal
Seal is currently a mystery. There is no genetic research so far conducted into seal. It is unknown how it is caused or which locus is responsible for it. Theories include seal being an allele on the K locus, recessive to K, potentially something like a faulty K allele that works similar to brindle, an allele on the A locus, or a modifier on an unknown locus that's causes A locus to partly show through on K/k dogs.
Seal coloring makes a black dog appear brownish with the pigment of the eyes and nose renaming black. The shades vary from slight brown to a shade almost as light as liver. There is usually a black stripe down the back and tail as well as the legs and they usually remain darker then the main part of the body. Seal dogs are born brownish and develop bronzing with age.
"Ghost" Tan
Ghost tan is thought to work similar to seal, where the K allele for some reason allows the A locus allele(s) to show through very faintly. A ghost tan dog would look like a normal tan point dog if the dominate K allele wasn't present.