It could. For example, bumblebee in the ball python is a combination of pastel and spider. But it was not gotten by crossing a snake with two copies of the spider mutant gene to a snake with two copies of the pastel mutant. It was gotten by crossing a pastel to a spider. The results of such matings are
1/4 normal
1/4 spider
1/4 pastel
1/4 spider, pastel (AKA bumblebee)

Crossing a snake with two copies of the spider mutant gene to a snake with two copies of the pastel mutant would produce all bumblebee babies.

Paul Hollander