Leatherback Zero Central Bearded Dragon
One animal carrying both genes. Each one is inherited separately, so this combination is made by bringing them together rather than being a gene of its own.
Documented health finding on one of these genes
Leatherback. Two copies of this gene produce a Silkback, an animal with essentially no scales. Silkbacks are widely documented to shed with difficulty, to be prone to skin damage and retained shed around the toes and tail, to lose moisture faster than a scaled animal, and to be more sensitive to handling and to UV exposure. Many keepers and welfare bodies consider the combination one that should not be produced.
The two genes
How one is made
Both genes have to come together in the same animal. The pairing that does it most directly is Leatherback × Zero, which works out every outcome and its odds.