Coat Color Inheritance in the Anatolian Shepherd Dog
by Mary M. Ewald
The Anatolian Shepherd dog is a livestock guarding dog with origins in Turkey. They are being used extensively across North America to protect flocks of sheep, goats, and rare species against coyote, bear and other predators.
Exact origins of the breed are unknown, but apparent progenitors have been depicted in Assyrian bas relief's dating from 2000 B.C. Roman war dogs of Molossian (Mastiff) type were probably left behind after invasion of Turkey to intermingle with native dogs. There is also strong evidence of a link with other European livestock guarding breeds such as the Maremma-Abruzze, Komondor, Kuvasz, Caucausian Ovtcharka and Shar Planinetz -- all of which evolved from the Tibetan Mastiff.
Modern Turkish shepherds choose dogs based on ability, with little regard to color, but there appears to have been a time when dogs were bred to match the color of their charges so that they would blend in and deceive predators. Localized regions in Turkey exist where certain colors are more often found, but an increased mobility of the people has led to a blending of these gene pools; some very interesting color patterns have emerged.
Coat color in the dog is inherited through somatic cells and there is no evidence of linkage of coat color genes. Four loci which may contain any of four alleles, and six loci that may contain two alleles each have been identified. Epistasis appears to be very common in a system that involves many types of dominant and recessive alleles. Incomplete dominance is often expressed. Color mutations are rarely observed, but can never be ruled out.
There are two major types of pigment in dog coats. These are yellow and dark (black or brown). All color variations arise from combinations of genes utilizing these pigments. Melanin, the actual pigment in the coat, is formed by the interaction of a chromogen or "color base" and an enzyme. The pigment is distributed to varying degrees in either or both the cortex (outer layer) or the medulla (inner layer) of the hair giving different color effects.
The ten categories of genes involved in canine coat color currently identified are as follows.
In 1989, Roy Robinson of England published a paper in Genetica on Anatolian Shepherd Dog coat color inheritance. His data were drawn from extensive records maintained by breed clubs in the United States and England. His results have helped to clarify the many phenotypical expressions of color observed by breeders and enthusiasts, but he did not deal with all coloration's that have been observed. In addition, he cites the occurrence of a "single blue diluted dog . . . bred from normal fawn parents." This dog was from one of my litters and also had a blue littermate. One parent was fawn with a black mask and the other was white. The fawn parent came from a line that has produced several "dilute" offspring. Robinson's conclusions that the blue expression was a result of a dd genotype is probably still correct, but he makes the assumption that both parents were heterozygous for this trait. The white dam never produced any dilute offspring when bred to different males, and the dilutes produced by the sibling of the male were sired by males totally unrelated to the white female. My personal belief is that the dilute coloration's of slate blue with a grey mask and light liver with a liver mask are a result of epistasis or a rare polygenic combination. There have been only seven dogs of these phenotypes reported out of over 3500 dogs registered, and more than half of these came from one line.
Robinson reports that the fawn color (with black mask) most often observed in Anatolian Shepherd Dogs is produced by the dominant yellow allele Ay which is dominant to the wild-type allele for wolf-grey coloring, A+ of the agouti series. Many of the dogs of this breed also have white markings on the face, legs, chest and belly which are inherited as a recessive to the non-white. The white pattern is attributable to Ay allele for which piebald has great variations in expression. The dogs vary from fawn with white paws to white with fawn patches.
The Anatolian Shepherds, sometimes called Akbash that are referred to as white are in fact genotypically cream. The white color is inherited as recessive to fawn with the allele cch (chinchilla) degrading the yellow pigment to cream or white, while leaving the skin and nose black. White puppies are often born with faint piebald markings or patches which fade with age. The reverse is also true with white puppies turning fawn with age.
Robinson disagrees with Little on the inheritance of the facial mask. He believes that the mask is a polygenic trait, while Little reports that it is a monogenic result of the gene Em.
Robinson's report does not deal with the genotype for brindles or blacks that I observed in Turkey, nor does he mention the ticking that is so often found in the white patches of the neck and legs. In fact, during a recent trip to Turkey, I observed a brindle extreme piebald male with ticking over his entire body.
Robinson's results were as follows:
The occurrence of brindle coloration in the Anatolian Shepherd Dogs is relatively rare in the United States. Little reports that a monozygous ebr codes for this pattern and that it is epistatic to e and incompletely hypostatic to E and requires the presence of the Ay gene. This claim seems to be supported by the observations in the Anatolian Shepherd Dog. All brindle dogs that have been bred to totally unrelated Ay__ dogs have produced litters that are close to 50% brindle.
The black Anatolians that have been observed in Turkey may be a phenotypic expression of a very dark brindle with or without a homozygous BB pair of alleles to code for black. There is no information currently available on the pedigrees of black dogs. The possibility also exists that these are not purebred dogs, however, the Tibetan Mastiff--an Anatolian ancestor--commonly exhibits a black coat.
Overall body ticking in two brindle piebald siblings is probably due to inbreeding of dogs carrying the T allele. Leg ticking is often observed, but body ticking is not.
Because this is primarily a working breed of dog, little attention should be paid to color, and far more to soundness and temperament. it is probably optimistic to expect all breeders to feel this way and already there is a certain prejudice towards fawn dogs by both breeders and judges. One of the reasons for this is lack of understanding the genetics of coat color that leads to the great diversity and almost unlimited combinations observed.
The Inheritance of Coat Length
Crawford and Loomis reported on the inheritance of short or long coat in another Molossian-type breed, the St. Bernard. They concluded that inheritance is based on simple autosomal inheritance of the dominant (short coat) or recessive (long coat) alleles.
The Anatolian Shepherd Dog shows the same mode of inheritance for coat length. Short coated dogs can produce long coats, but long coated dogs never produce short coats. The amount of feathering on the legs, density of the coat and length of the mane do not appear to be directly related to the length of coat except in a slightly proportional manner. Short coated dogs can have heavy feathering, and long coated dogs may have less. This leads me to suppose that the other coat characteristics are on separate chromosomes.