Solid can carry for parti-color, but parti-color CANNOT carry for solid. A solid carrying two genes for solid can only produce solid and bred to a parti-color will only result in solid color puppies, but ALL those puppies will be carriers for parti-color. Breed a solid that carries a gene for parti-color to a parti-color and some puppies will be solids and some will be partis, but all the solids will carry for parti-color.
Roan can carry for open marks, but open marks cannot carry for roan
Notice I did not include ticking. Ticking is by some considered to be a form of roaning, by others to be a different gene. Those who feel it's a different gene consider it recessive to roan but dominant over open marks.
Also, there are color gene modifiers that set theories askew.
Example: Dark roan is dominant over light roan therefore two light roans cannot produce dark. However, we all know lighter roans producing darker roans. What is in action here are modifiers that affect the extension of color. Similar to why some tan marked dogs have a lot of tan, others just have small spots, why some tan-marked dogs are "smokey" on their tan and others are perfectly clear, etc..
The genes for black (B) and liver (b) are the same gene with black being dominant. They affect skin color as well as coat.
The gene for red is not the same as the gene for black and liver. Red (e) is recessive to the gene for "no red" (E). If a dog carries the dominant gene for "no red", it will be black coated(unless it also carries the two recessive genes for liver, in which case it will be liver coated.) If it carries two genes for red (e) it will be red.
This is why you can have reds with liver noses. Liver nosed red bred to a liver or to a black that carries for liver, such a breeding will produce solid livers. If that liver carrier also carries for red, such a breeding will produce liver nosed reds as well.
The genes for actual color (liver, black, red, tan marks) have nothing to do with the genes for markings (solid, parti-color).
The exception to this rule is that red, more than black or liver, seems to be more heavily affected by any gene modifier that reduces pigment. Solid reds have something like a 30% higher chance of retaining white on their face than black or liver puppies do, and red/orange parti-colors tend to have more overall extension of white than black or liver do.
BTW, a red or red parti-color that is the product of two tan-marked parents carries two genes for tan, therefore it is genetically a "red and tan" or "orange roan and tan".
Briefly, Sable is a gene in the "A" series. The specific gene is called "ay". The "ay" gene is very common in some breeds....hounds, collies, shelties....but rare in Spaniels.
Sable is inherited in Cockers the same way it is in Collies. You need a sable gene ("ay") combined with the tan gene ("at") for shaded sable to occur. Clear sable looks just like a "normal" red (ee). Some of those reds in the ancestry are probably clear sables.
Dark shaded sables tend to be very dark at birth and sometimes look like black and tans with the tan gone a bit awry. As they mature, the gold/red extends until the body coat is red and the jacket hairs are black tipped.
The Germans have taken quite a fancy to sable and they have become quite commonplace. They are producing both black shaded sable and liver shaded sable. The foundation stock in Germany that produced this color [in English Cocker Spaniels (ECS)] came from Squier's kennel here in the US. Mr. Squier acquired his first sable from a breeder in England.
It is felt by many purists that sable is an inappropriate color for ECS as it implies an impurity.....perhaps a cross at some point to a beagle or other similar type hound. Existing sables today, however, have been bred pure for many generations such that if there was an impurity, it is so diluted as to have no discernible influence on the breed, save the color.
The ECSCA, I believe, does recognize sable and sable parti-color (which I have not seen but understand is stunning) as valid colors although not without it's diehard critics.
Sable can also be liver shaded as well as black shaded although I have not seen any mention of liver sable being known of or accepted here in the US.
From a practical point of view, shaded sable (as opposed to clear sable which looks like normal red, sometimes with a dorsal stripe) is NOT what I would want for a field dog as the color is VERY hard to see. On the other hand, any solid color as well as very dark roan is difficult to see at least part of the year. So any argument on that account loses it's validity.
Folks interested in sable will find the most and possibly the best in
Germany. They have become quite common there and are generally of excellent
type. Most pedigrees show ancestors from prominent English and European
kennels that could be easily utilized with our imports here, if anyone really
wanted to pursue this.