In our breed it is often said, "The color of the Portuguese Water Dog is magic!" Indeed, we enjoy a wide variety of colors, shades, and white patches in our breed. But other than the hidden surprises issued by recessive genes, coat color in dogs can generally be explained through color studies conducted in the mid-20th century.
Before we start, let’s get some basic terms under our belts. The phenotype is what you see, as compared to the genotype—the genes the dog actually carries. Coat color is polygenic, meaning more than one gene series are involved. At least eleven gene series have been identified to impact coat color in dogs, all of which have at least two alleles (variations). The alleles of each gene series can be ranked by dominance. A dog inherits one gene from each gene series from each of his parents. The most dominant genes are the ones expressed (phenotype). However his genotype contains both the dominant and recessive, and he could pass either onto his offspring.
Getting Genetically White Pups
The most easily understood color series is the "B" series, which dictates whether a dog is genetically black, brown or white. In a breed with a wide variety of colors such as the Portuguese Water Dog, genetically-black and –brown dogs may be confused since black dogs with color-modifier genes may actually appear to have brown, beige, or white coats! The true test of whether a dog is black or brown is the color of its nose. If the dog has a black nose, it is a genetically black dog no matter, and the dog may produce black-coated puppies. A brown nose indicates a genetically brown dog who only carries the recessive brown gene (no black) and must be mated to a dog carrying black (B) to produce black puppies. A white (s) dog must have a black nose and can only produce genetic white puppies when mated to another white (s) or a (Bs) or a (bs).
Let’s look at how a mated pair of dogs passes on the "B" series to its offspring. For this example, let’s say each parent is homozygous (has two of the same alleles). One is black (BB), and one is white (ss). Remember, each parent passes on only one of it’s two genes to each offspring! In these types of diagrams, one parent is represented on the top line, and the other down the left side.
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In this example, all of the off- Statistically, 100% of the pups will be black (Bs), able to produce phenotypically black or white pups. providing the mate carries white. |
If we were to mate two of these heterozygous pups together, we Statistically, 25% of the pups will be homozygous black (BB), unable to produce anything but phenotypically black pups. 50% will be heterozygous black (Bs), able to produce both black and white pups, providing the mate carries white. 25% will be homozygous white (ss). |
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GENE SERIES
The S series dictates the amount of white spotting in the coat. Often, we will say a dog is white with colored patches. In reality, it is a colored dog with very large white patches!
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Some breeders waste a lot of effort trying to breed pure white dogs from parti or extreme piebald stock. While this method of breeding will increase the size of white patches, some dark will always appear somewhere on the body. True white dogs are S- (solid color) with extreme color modifiers in the other gene series. As a note of caution, skin under white patches is generally pink from lack of pigment and is subject to sunburn.
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white collar and forelegs; up to 40% white | |
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40 - 80% white | |
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more than 80% white with some color
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