Leopard complex
The Tigerschecken complex, also called 'the Leopard Complex, comprises several caused by the same gene Scheckungsmuster the horse. Among them completely white horses and those with Varnish Roan drawing fall. The Scheckungsmustern often appear small round dark spots on a white background.
Features
There are horses without visible Scheckungsmuster that only show the darker color. Others have a different-sized oval, emanating from the rump white patch ( saddle cloth ), which has spread among the brightest horses over the entire horse. Normally, the skin is dark with white fur pink and dark fur, but the dark skin often extends a little way from the dark fur out in the areas where the fur is white. Often, in the white saddle pad dive small, penny - up on apple big round dark spots on a light background. Conversely, there are also small bright dots on the dark skin areas. The hooves are often streaked for white and black spots at the edge of the hoof. Dark skin areas are usually lighter in the course of life as more and more white Stichelhaare sprout in them.
If the Tigers check Engen present homozygous, it leads to congenital night blindness. Heterozygous animals that possess the gene only once, are not affected.
Variations
Tiger snowflakes, almost monochrome
Mature Varnish Roan
White Born
The horse is born white and does not undergo a color change. White babies are always homozygous for the gene.
Full Tiger
As a full- Tiger (English Leopard) refers to horses that have on white background many small usually round dark spots.
Pelmet Tiger
As pelmet Tiger (English: Blanket from Turkish: çaprak, saddle blanket ') are referred Tigerschecken in which a significant portion of the horse's normal color displays, while a rounded portion of the croup is starting white. The size of the saddle pad is very variable, sometimes followed by spots within those.
Snowflakes Tiger
The snowflakes Tiger (English: Snow Flake) has spread throughout the body small white spots.
Varnish Roan
Similar to the mold also appear at Varnish Roan over the years more and more white hairs in the coat. Dark leaving only the skin areas where bones are close to the skin. These are, for example, the front legs to the carpal joint. The dark color runs from the front in a point. On the hind legs, she reaches to the hock. There are also dark permanent locations on the leg extension front and rear ( elbow and knee ). In front face, a dark V remains, while the forehead and sides of the head are largely white. Mane and tail also remain slightly darker. → For the names of body parts, see: Exterior (horse)
- Mold in the phase of the Ausschimmelns: The face is bright as the first, especially in the area where the Varnish Roan the Dark V remains.
- Stichelhaariges Horse: The face is completely dark, the dark color ranges in the legs to the elbow or hip joint. They remain colored about the same, except for the fact that the amount of Stichelhaare changes with the seasons throughout the course of their lives.
- Rabicano: The stichelhaarigen areas are less extensive than in Stichelhaarigen horse and are primarily in the chest. The horses are not brighter in the course of their lives.
Monochrome Animals
Not every horse the gene affects the appearance.
Transitional forms
Since all of these colors are caused by a single gene, there are smooth transitions between them. Tigerschecken with dark skin areas can also always like the Varnish Roan lighter in the course of their lives.
Pintaloosas
Horses who have next to the tobiano gene nor a Tigerschecken gene are called Pintaloosas, a composition of the words Pinto ( American for " piebald " ) and Appaloosa.
Dissemination among the races
European Tigerschecke, European Appaloosa pony, Appaloosa, Knabstrupper, Colorado Ranger, and Nederlands Appaloosa ponies always have the typical Tiger check pattern, but the gene also occurs in the Welsh Pony Noric and the Pony of the Americas.
History
In a cave painting, which dates from about the year 18,000 BC, a horse is shown, which looks like a typical Tigerschecke. It was assumed that the points of the horse could possibly be meant only symbolically. Meanwhile, however, has been proven that it then actually already gave Tigerschecken.
In China Tigerschecken from Ferghana were called Heavenly horses and play a major role in Chinese art. An illustration of Lippizanerzuchtstuten 1727 shows not predominantly mold, as we are used to today, but horses of different colors, which also included a leopard spotted. In France, nobles, kings and saints were often depicted on Tigerschecken. Similarly, it was in England since the 12th century. In Denmark, Norway and Sweden are many works of art on which Tigerschecken are depicted. Denmark was in the 17th century Tigerschecken of Austria, but had, which is logical due to the genetic variance of the gene, problems to breed color pure. Therefore, the breed was abandoned. Of them today Knabstrupper come from. The Spaniards exported horses to North America, of which probably descended the horses, the Nez Perce bred the. Turn from them the Appaloosas descended from.
Genetics
The gene for the Tigerschecken complex is located on chromosome 1 of the horse, and with LP ( for English leopard spotting ) abbreviated. The known leucism origins MITF, Steel and Kit and oculocutaneous albinism type 2 were first excluded as the cause. Then, it was found that there is a mutation of the gene TRPM1 which causes expression of the gene in homozygous animals to 0.05 % of the normal levels of colored horses is reduced. The expression rate of heterozygous animals in between.
It is believed that the decreased expression of the gene disrupts either the function of the bipolar cells of the retina as well as the melanocytes, so that both the night vision of the homozygous Appaloosas and the typical Appaloosafarbe could be caused thereby.
Horses that have only one allele of the gene, usually have less white fur as homozygous animals. Nevertheless, you can not read them on appearance, whether an animal has one or two alleles of the gene, since the expression of the color is very variable.