Yellow belly and Mojave are both heterozygous versions of co-dominant mutations. The respective homozygous phenotypes are Ivory and sort of purplish headed leucistic.

I believe The Snake Keeper produced some yellow belly mojave’s but they where not white snakes, tending to indicate that even though the homozygous form of both is a predominantly white snake they are most likely unrelated genes involved (as opposed to some other white snake hets that might be different mutant versions of the same gene).

I believe the odds on an egg from yellow belly X mojave would be 25% chance Mojave yellowbelly, 25% chance just Mojave, 25% chance just yellow belly, 25% chance normal.