In the case of the brindle pattern, it's only recessive to the black so, in order for it to be in the genotype for more than a couple of generations without being expressed, you'd have to have a line that has only bred black to black, since at least 50% of the fawn offspring will show the brindle pattern if the black parent is also brindle.
Jade & the Smug Pug Circus
SmugPugs I Am Legend(9pts)Desert Moon's Triple Threat
Anmar's Give Me Liberty
SmugPugs Country Legend
SmugPugs Jazz Legend
Retired: CH Chubby Cheekers, Diva, Lily & Dazzle
Thanks SmugPugs. I need to get my head around this. I consider myself highly intelligent but the subjects of genetics gives me headaches!