Yeah, this is an 11-year-old thread, but I stumbled on it while looking for an article I read previously on the color genetics for brindle poodles.
What happen to the brindles prior to 1950's? 1950 is not that long ago. This makes me still believe brindles were added from other breeds. If you could find more info about brindles early one then I will believe this color to be orginal. I have old poodle books and they never mention brindles but then again these books are written by people who are breeding solid dogs so you know some history is left out.
My newest poodle is Hobbes, born September 2019, and is a brindle. I like to keep his body clipped to about 1/2 inch to better define the stripes, but his breeder tells me they will fade with age. I presume that's because the coat grows continuously and only new sable hair has the distinctive bands of color. But still, the stripes on his skin remain, and make a lovely chevron pattern on the shaved part of his tail.
He's fully registered in both AKC (as "black and silver") & UKC (as "brindle"). I also was wondering about the origin of the color variation. In the picture below he got his first two competition wins in UKC conformation (November 2020). [Note to self, continue training him to hold his tail up when gaiting.] His mom is a UKC Emerald Grand Champion and two of his littermates have finished their grand championships. I got him as an obedience prospect and my instructors all think he has loads of potential. He learns incredibly fast and is already starting to understand dumbbell retrieves, the full pile of scent articles, and short go-outs. Attentive heeling, as with any dog (I think) is a lifelong training and reinforcement task, but he's starting to get it.
I was reviewing his genetic report (Optimal Selection, now Wisdom Panel) yesterday and found some clues that might relate to the origin of brindle.
Trait: MC5R c.237A>T
Description: The dog carries one copy of the allele associated with heavy shedding and one copy of the allele associated low shedding. This genotype has no effect on a dog with furnishings, but non-wire-haired dog with this genotype is likely heavy or seasonal shedder. [NOTE: He tests AA/TT for furnishings, meaning he is likely to express them--as if you can tell on a poodle.]
Trait: Colour Locus K - Dominant Black
Genotype: KB/ky || KB/kbr || kbr/ky || kbr/kbr
Description: The dog is genetically dominant black or brindle.
Trait: Colour Locus A - Agouti
Description: The dog is genetically sable.
[By the way, he does NOT a carry merle: m/m]
The dog carries one copy of an allele typically associated with floppy ears, and one copy of an allele typically associated with pricked ears.
So, an ancestor that is sable, sheds heavily, and has prick ears would be the suspect. But, as with merle poodles, if you lie about parentage on the paperwork and breed several subsequent generations, the genetics are otherwise indistinguishable from registered poodles.
He tests "clear" of all the disorders found in in multiple breeds of dogs--starting at page 5 and continuing to page 14. The full genetic report runs 22 pages in PDF format.
But ya know, closed registries, especially in rare breeds, are damping down genetic diversity. My guy tests as highly diverse, though I can't check the current figures because Optimal Genetics hasn't restored that feature (scheduled for early 2021).
And here he is, earning 197.5 in his second CDSP Novice test at 13 months old: