Buckskin and Perlino
The buckskin has a golden or yellow coat with a black mane and tail. It's the result of one cream gene on a bay base (CRcr).
This gene is incomplete dominant, which means that the resulting dilution of the coat will be different with one and two copies. One copy only affects red, while two, red and black. This is why the bay's red coat is diluted but not the black points.
A bay base plus two copies (CRCR) will result in a perlino, with a white or cream coat and a slightly darker mane and tail.
Here is a punnett square showing how the gene behaves:
| cr | CR | |
|---|---|---|
| cr | Bay (cr/cr) | Buckskin (cr/CR) |
| CR | Buckskin (CR/cr) | Perlino (CR/CR) |