Here's how it works:
* Genes: Every dog carries two copies of each gene, one from each parent.
* Recessive Genes: Some genes are recessive, meaning they only show up in the offspring's appearance if they inherit two copies of the gene.
* Carrier Parents: Even though your two solid-colored dogs don't have spots, they could both be carrying the recessive gene for spots. They'd be considered carriers.
* Puppy Inheritance: If both parents pass down the recessive gene for spots to their puppy, then the puppy will express the spotted trait.
Example:
* Imagine a gene for coat color, where "S" represents the dominant solid color gene, and "s" represents the recessive spotted color gene.
* Both parents could be "Ss" (carrying the recessive gene).
* If the puppy inherits an "s" from each parent, it becomes "ss" and will have spots.
It's important to note that the specific pattern of spots and their color will depend on the specific genes involved, which can be quite complex.