Which year confirmed the Yellow Belly gene's co-dominant status?

2003

The definitive classification of the Yellow Belly gene as co-dominant (previously noted as demonstrating incomplete dominance) was established in 2003. This confirmation was achieved through the focused breeding efforts of Dan and Colette Sutherland, associated with TSK. They specifically bred two snakes already expressing the Yellow Belly trait together. The outcome of this pairing was crucial because it produced a visually striking new form, confirming the mechanism of inheritance. The resulting offspring was drastically different from a single-gene expression, clearly demonstrating the enhanced effect associated with having two copies of the gene, thus solidifying the co-dominant designation.