Any time one established breed is crossed with another, for whatever reason, part of that breed's characteristics are inherited through the DNA structure, whether it be color, structure, working ability, temperament, disease, or any other heritable trait. The only way to prove whether a dog carries a certain inherited breed trait is by DNA testing. That DNA testing would be the only way to determine whether litters registered as purebred actually were, and DNA testing wasn't available when white first appeared as a coat color in miniature Schnauzers.
From pedigree research the "white" (gelb or "yellow" as it was called in early German records) gene was introduced into the Miniature Schnauzer breed mainly through a German black Champion Miniature Schnauzer named Peter V Westerberg (PZ604), born in November 1902. Peter was obviously carrying one "e" gene because it is recorded that he was bred to a female named Gretel VD Werneburg (PZ1530) (color unknown) and produced a "yellow" female pup named Mucki VD Werneburg (PSZ 8) born October 1914. Mucki was bred to a grandson of Peter named Pucki VD Werneburg, a dark S&P PSZ12 who produced the black German Champion Peterle VD Werneburg, PSZ11 born June 2, 1916, who also had to have the "e" gene since his dam was yellow. Peter V Westerburg or his grandson, Peterle can be traced to in nearly every Miniature Schnauzer line researched in AKC records. For example, if you trace every ancestor in the 5th generation of Dorem Display, you will find every dog goes back to Peter Von Westerberg. With so many linebred crosses, it is statistically impossible to eradicate the "white" "e" gene by visual appearance alone. Those former claims that the "white" gene has been eradicated from the Miniature Schnauzer lines could not be proven, because the DNA test was not available until 2006.
There is no known factual data to back up the above assertion that 'gelb' equals 'white'. The originators of the breed in the late 1800 and early 1900s in Germany wanted an EXACT duplicate of the Standard Schnauzer. The Standard Schnauzer has never appeared in the white or even 'gelb' color variety. The original Schnauzer Club in Germany disqualified whites and told breedes of Parti colors and solid whites to not continue to produce those colors as they went against the ideal breed standard.
There are two forms of melanin (pigment) in mammals' hair coats. The first is called eumelanin. The base form of eumelanin is black. Eumelanin can also appear brown (often called liver in dogs) or blue-gray. The second pigment, which varies from pale cream through shades of yellow, tan, and orange/red is called phaeomelanin.
All dogs have alleles at every locus. Not all proposed alleles have been proven to exist. The generally recognized color loci in dogs are referred to as: A (agouti), B (brown), C (albino series), D (blue dilution) E (extension), G (graying), M (merle), R (roaning), S (white spotting) and T (ticking.) There may be more, unrecognized gene series, and in a given breed, modifying factors may drastically affect the actual appearance. The newest proposed locus is the K locus for dominant black in certain breeds, including the Miniature Schnauzer.
White Miniature Schnauzers do not possess the "d" allele, which is commonly known as the Dilution gene responsible for diluting both eumelanin and phaeomelanin pigment. This stands to reason because true white Miniature Schnauzers have black skin pigment and dark eyes.
Genotypes for the white Miniature Schnauzer are proposed as follows showing they can "carry" for any of the other 3 colors of solid Black,B&S or S&P:
|aw,aw||D,D||e,e||k,k (white carrying for S&P)|
|aw,at||D,D||e,e||K,k (white carrying for S&P, B&S, and black)|
|at,at||D,D||e,e||K,k (white carrying for B&S, and black)|
This "e,e" genotype for the white Miniature Schnauzer proves that all of the other 3 colors can carry a gene for the white and also that any of the 3 colored schnauzers bred to another schnauzer of any color that is carrying one "e" gene can produce a white puppy from that mating.
Therefore, a B&S with the genotype of at,at; E,e; K,k bred to another B&S with the same genotype can produce a white puppy. The statistical odds are:
Mating 2 whites together will produce 100% white puppies because white is a double recessive gene phenotype.
Some of the early breeders of Miniature Schnauzers thought the white puppies were albino because when they are first born, they have pink skin and noses. Many early breeders destroyed them at birth mistakenly thinking they were albino and therefore defective. Those who did not destroy them found that within a few hours and days their skin pigment turned to black on their noses, around the mouth and eyes and the pads of their feet and bellies.
Through rumors circulated that the white minis carried defective or lethal genes similar to the blue merle dogs or white boxers and that the white miniature schnauzers have medical problems and deafness, the truth is the white minis have no different health problems than their colored counterparts.
Another rumor that has spread throughout North America is that the White Miniature Schnauzers were fraudulently bred up from West Highland White Terriers to get the white coat color. "...Therefore we can assume that the Miniatures are not the result of medium sized Schnauzer matings but of an outcross of Schnauzers to Monkey Pinschers" from "History of the Schnauzer and Miniature Schnauzer" by Joseph Schwabacher, copyright 1930, page 35, translated from the German for the Schnauzer Club of America. So Miniature Schnauzer came from a combination of black or pepper & salt Schnauzers, and Monkey Pinschers, now known as Affenpinschers which are black, gray, silver, red. black and tan - not white. White was not an original color or wanted color in the breed.
The original breed standard of the country of origin (Germany) did not recognize white and the originators of the breed did not intend to recognize white or it would have been recognized originally.
The White Miniature Schnauzer may be shown in conformation events in the USA in international dog shows sanctioned by the IABCA (International All Breed Canine Association). White Miniature Schnauzers are still considered a "rare" breed in the U.S. and may also be shown in the rare breed classes in IABCA.
Throughout most of the rest of the world, the White Miniature Schnauzer may be shown in Conformations shows sanctioned by the FCI in International competitions. The White Miniature Schnauzer is becoming very popular in Europe as a show dog. The White Miniature Schnauzer Initiative was established in 2006 in Germany for friends and breeders of the White Miniature Schnauzers worldwide to promote interest and provide an informative network for sharing ideas and information and to give breeders the opportunity to exchange and expand the gene pool of the white Miniature Schnauzers worldwide.