Exploring Dog Coat Color Genetics in Depth

Dog coat color genetics is a complex yet fascinating field that has captivated many dog enthusiasts. The genetics of coat color are determined by multiple genes and their interactions, which can result in a wide range of colors and patterns.

The genetics of black coat color is relatively simple and is determined by the presence of the melanistic gene. This gene codes for the production of the pigment eumelanin, which gives the coat its black color.

The genetics of red coat color, on the other hand, is more complex and is determined by the interaction of multiple genes. The red gene is recessive to the black gene, meaning that a dog must inherit two copies of the red gene (one from each parent) to express the red color.

The interaction between the black and red genes can result in a variety of colors, including liver and blue. These colors are the result of the interaction between the eumelanin and pheomelanin pigments, which are produced by the combination of the black and red genes.

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Dog coat color genetics is a complex field, but understanding the basics can help you appreciate the incredible diversity of coat colors in dogs.

There are two basic pigments that create all the different coat colors in dogs: eumelanin and phaeomelanin. These pigments are produced by melanocytes, which are specialized cells found in the hair follicle.

Each hair follicle is surrounded by many melanocytes, which make and transfer the pigment melanin into a developing hair. Dog fur is colored by two types of melanin: eumelanin (brownish-black) and phaeomelanin (reddish-yellow).

There are eight genes in the canine genome that have been associated with coat color, and each of these genes has at least two known alleles. These genes work together to control the production and distribution of eumelanin and phaeomelanin, resulting in the incredible variety of coat colors we see in dogs.

Here are the eight genes associated with coat color, along with a brief description of each:

Understanding the basics of dog coat color genetics can help you appreciate the incredible diversity of coat colors in dogs and even predict the color of your puppy's coat.

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Pheomelanin is the pigment responsible for red and yellow pigmentation in dogs.

In yellow Labradors, the E locus determines whether the phenotype due to the third genetic locus affecting coat colour will be evident, and it's only visible in the absence of eumelanin.

Eumelanin, on the other hand, is the dark pigment found in black and brown coats.

The three recognised colours of Labrador Retrievers result from differences in two genetic loci that affect pigment expression, specifically those affecting the colour of the dark pigment, eumelanin.

Two genetic loci, the B (brown) locus and the E (extension) locus, work together to determine the colour of a Labrador Retriever.

The B locus is responsible for the variation displayed by this locus, which is observed in many mammals, reflecting a so-called 'dilution', a lightening, of black eumelanin to a brown colour.

The E locus, on the other hand, determines whether eumelanin is deposited in the fur or solely in the skin.

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A recessive mutation in the E gene truncates the protein, producing a non-functional receptor incapable of directing eumelanin deposition in the fur, resulting in a yellow coat.

The combination of these two genes determines the colour of a Labrador Retriever, and is widely used as an example of epistasis.

Here's a summary of the two main pigments:

Color gene interactions are a fascinating aspect of dog coat color genetics. Two basic pigments, eumelanin and phaeomelanin, are responsible for the vast array of coat colors seen in dogs. These two pigments are the result of genes manipulating the production and distribution of melanin.

The interaction between eumelanin and phaeomelanin can result in a range of colors, from black to red. The E (extension) locus plays a crucial role in this interaction, with four alleles that determine the intensity of eumelanin and phaeomelanin. The four alleles, in order of dominance, are: melanistic mask (Em), grizzle (Eg), black (E), and red/cream (e).

A dog's coat color is determined by the interaction of multiple genes, including the B (brown) locus, which controls the production of brown pigment. The B locus has two alleles, B and b, with B being dominant and b being recessive. Dogs with the genotype BB or Bb will have a brown coat, while those with the genotype bb will have a black coat.

The D (dilute) locus also plays a role in color gene interactions, with two alleles, D and d, that determine the intensity of eumelanin. Dogs with the genotype D/D or D/d will have a diluted coat color, while those with the genotype d/d will have a more diluted coat color.

Here is a table summarizing the color gene interactions:

As you can see, the interaction between eumelanin and phaeomelanin, along with the influence of other genes, results in a wide range of coat colors. Understanding these interactions can help breeders predict the coat color of a dog's offspring.

The genetics of dog coat colors is a complex but fascinating topic. The A (agouti) locus is responsible for different coat patterns in dogs, including the agouti protein that controls the release of melanin into the hair.

The E (extension) locus, also known as MC1R, is associated with the black facial mask of many dogs as well as yellow or red coats. The four alleles of this gene in order of dominance are: melanistic mask (Em), grizzle (Eg), black (E), and red/cream (e).

The K (dominant black) locus controls dominant black, brindle, and fawn colors, which were previously linked to other genes like Agouti. This relatively new locus includes colorations like sable and wolf-sable.

Here's a breakdown of the main coat colors and their associated loci:

The combination of these loci determines the final coat color of a dog, and a dog of one color may carry hidden colors in its gene pool that may appear in its pups.

Brown is a coat color that's caused by a gene called tyrosinase related protein 1 (TYRP1). This gene affects the color of the eumelanin pigment produced, making it either black or brown.

The TYRP1 gene is an enzyme involved in the synthesis of eumelanin, and each of the known mutations eliminates or significantly reduces its enzymatic activity. This modifies the shape of the final eumelanin molecule, changing the pigment from a black to a brown color.

There are four known alleles at the B locus, which determines the color of the eumelanin pigment. The B allele is dominant to the b allele, and it codes for a black eumelanin pigment.

The b allele, on the other hand, codes for a brown eumelanin pigment. An animal with any matched or unmatched pair of the b alleles will have brown, rather than black, hair and a liver-colored nose, paw pads, and eye rims.

Here are the known alleles at the B locus:

It's worth noting that the different brown alleles may not cause specific shades or hues of brown, and it's unknown whether they do.

The dilute gene is a recessive gene that affects the intensity of a dog's coat color. It's a mutation in the melanophilin (MLPH) gene that causes a dilution of eumelanin, resulting in a paler colored coat.

This gene determines the intensity of pigmentation, with the D (normal, wild-type MLPH) allele resulting in not diluted colors and the d (defective MLPH) allele resulting in diluted colors.

The dilute gene can occur in almost any breed, but it's most common in breeds that have a blue gene. Some breeds that are commonly known to have dilution genes include Italian greyhounds, whippets, Tibetan mastiffs, greyhounds, Staffordshire bull terriers, and Neapolitan mastiffs.

The dilute gene can cause a range of effects, including a dilution of black eumelanin to bluish grey and a dilution of brown eumelanin to taupe or "Isabella". Phaeomelanin is also affected, but to a lesser extent, resulting in a dilution from red to yellowish tan.

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Here's a breakdown of the effects of the dilute gene:

The dilute gene is completely dominant to the d allele, meaning that a dog with one copy of the D allele will not have a diluted coat, even if it's paired with a d allele.

The Harlequin coat color is a unique and striking pattern found in Great Danes. It's caused by a missense mutation in the 20S proteasome β2 subunit at the H locus.

The Harlequin allele is specific to Great Danes and affects both eumelanin and phaeomelanin equally. This means that the patches of color on a Harlequin dog are white and not just reduced in intensity.

Harlequin dogs (H/h M/m) have the same pattern of patches as merle (h/h M/m) dogs, but the patches are white. The Harlequin allele has no effect on non-merle m/m dogs.

There are two alleles that occur at the H locus: H = Harlequin and h = Non-harlequin. H/h heterozygotes are Harlequin and h/h homozygotes are Non-harlequin.

Here's a summary of the Harlequin alleles:

This means that all Harlequin dogs are H/h, as breeding data suggests that homozygous H/H is embryonic lethal.

The C locus is a gene that plays a crucial role in determining a dog's coat color. It's associated with the production of phaeomelanin, a red-brown protein related to melanin production.

There are five alleles that have been theorized to occur at the C locus, but research suggests that multiple alleles are highly unlikely. In fact, all dogs are homozygous for Normal Color production, excluding those that carry albinism.

The C locus is linked to the production of full color, chinchilla, extreme dilution, blue-eyed albino/platinum, and albino. However, it's essential to note that these alleles are not as straightforward as they seem, and their effects can vary.

Here's a breakdown of the different alleles associated with the C locus:

Keep in mind that these alleles can interact with other genes to produce a wide range of coat colors and patterns.

Nose colors can be just as fascinating as coat colors. A dog's nose color can give you a clue about its genetics.

Here's an interesting read: Dog Nose Colors

The most common nose color is black, but it's not the only one. A "butterfly" nose, for example, is a bright pink patch lacking pigment on the skin of a dog's nose.

Butterfly noses are randomly positioned and can cover any number of noses, from a tiny pink blob to almost the entire nose. They're often seen on dogs with extreme white spotted patterns.

A "Dudley nose" is a dog with a loss of pigment on its nose. The pigment loss typically starts in the middle and spreads outward, covering almost the entire nose of some dogs.

Dudley noses are common in black-nosed dogs and are particularly associated with the recessive red gene. They're not as bright pink as butterfly noses or liver dogs' noses.

Here are some common nose colors and their characteristics:

Urajiro is a unique coat color pattern found in some dog breeds. It's characterized by a reduction or absence of phaeomelanin production on the cheeks and underside.

The U locus is responsible for this pattern, with two alleles: U and u. Urajiro is thought to be recessive to u, but more research is needed to confirm this.

The U allele is associated with the urajiro pattern, which is expressed in tan areas of the dog's coat. It doesn't affect black pigment.

Here are the alleles associated with the U locus: