What percentage outcome is the Homozygous or Super Yellow Belly (YB/YB)?

25%

When two snakes identified as standard Yellow Bellies (both being heterozygous, YB/wt) are bred together, the genetic outcomes follow classic co-dominant inheritance rules. Each parent has a 50% chance of passing on the YB allele and a 50% chance of passing on the wt allele. Mathematically, this results in four potential combinations: YB from Parent A and YB from Parent B (YB/YB), YB from A and wt from B (YB/wt), wt from A and YB from B (YB/wt), and wt from A and wt from B (wt/wt). Grouping these results yields a 25% chance for homozygous (YB/YB), 50% chance for heterozygous (YB/wt), and 25% chance for normal (wt/wt) offspring. The resulting YB/YB snake carries two copies of the gene.