ФОРУМ ЛЮБИТЕЛЕЙ КОЛЛИ И ШЕЛТИ

Вот здесь можно посмотреть родословную и фото, что бы понимать как выглядит тигровый шелти.

http://www.barloshelties.com/brindle.html

как выглядит тигровый шелти.

Chiara
По данному шелти однозначного ответа нет. Некоторые породники высказывали предположения, что возможно примесь салюки......но четких доказательств как примеси так и её отсутствия нет... В принципе это демонстрация так называемых потеряных окрасов......т.е для того что бы подумать может не зря породники ещё на стадии образования породы поставили ограничения по окрасам и закрепили это в стандартах?

хотя в шелти всегда все не просто, ......даже в одном помете может родиться и "дворик" и чемпион

How It Works:
The K series is a newly recognized color gene, that was not identified by Clarence Little. It is one of the β-defensin genes, which are generally involved in immune function and have not previously been associated with coat color in animals. The K series is responsible for the dominant black that Little assigned to the A gene. Brindle color, assigned by Little to the E gene, segregates perfectly as an intermediate allele of the K series.
The K series, like the A series and E series, is involved in pigment switching between eumelanin black and phaeomelanin tan. Dogs with at least one copy of the dominant KB allele will be black in all pigmented areas of their body. Recessive to KB is kbr, which in the absence of KB results in brindle in the parts of the coat that are tan because of their A series genes. The most recessive allele is ky
, which allows tan/sable, as determined by the A series genes.
At The DNA Level:
The ky allele appears to be the ancestral allele in this series. The KB allele is associated with a deletion in the DNA, that causes a glycine amino acid (∆G23) to be missing from the resulting protein. Although identification of the kbr mutation has not been published, brindle color segregates as an intermediate allele in the K series.
However, the ∆G23 deletion is not exclusively associated with the KB, as more recent work documents that at least some brindle dogs carry a copy of the ∆G23 deletion.
Gene Interactions:
The K series black is epistatic to the A series, and in the presence of a KB allele, the dog will be black regardless of its A series alleles. Both kbr and ky allow
expression of the A series alleles. But if the dog is kbrkbr or kbrky , he will be brindle in any areas of A series tan.
Thus an ay dog would be brindle, and an atat dog would be black with brindle points.
Cautions and Comparisons:
KB produces the common black of Border Collies, but is not found in Shelties. In view of the dominance of kbr allele over the ky allele, the Sheltie breed standard’s disqualification for
brindle makes perfect sense. Unless a brindle Sheltie is the result of a new mutation, or the unlikely result of brindle being hidden through multiple generations of bicolors, a brindle Sheltie, because of its genetics, is unlikely to be purebred.
Since a mutation responsible for brindle has not been identified, explanations of the K series, especially of brindle, are incomplete, and may be modified by the findings of future research
According to our current understanding, a Sheltie cannot have a hidden brindle allele unless it is a bicolor. But occasional brindle dogs show up who appear to be Shelties. If they are, in fact, purebred
Shelties, either our understanding of brindle inheritance is incomplete, or their color is the result of mutation.

просто специалисты не так однозначны в этом вопросе

Соболиный ген не может быть в скрытом состоянии у колли и шелти, не может прятаться за триколором, поэтому от двух триколорных собак никогда не родится соболь. .

Как от двух биколоров появился триколор - тоже непонятно.