Granite Jaguar Carpet python
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 findings on these genes
Jaguar. Animals carrying a single copy of Jaguar — which is every animal sold as a Jaguar — are widely documented to show neurological signs: head-wobble, corkscrewing and disorientation, more pronounced under stress and while feeding. The severity varies between individuals, and it does not reliably improve with age. This is associated with the gene itself rather than being an occasional defect.
Jaguar. Two copies are understood not to be viable. Breeding two Jaguars together is expected to lose about a quarter of the clutch, and every surviving animal from such a pairing that shows the morph is a single-copy Jaguar.
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 Granite × Jaguar, which works out every outcome and its odds.