Dominance — A relationship describing which phenotype appears in a heterozygote carrying two different alleles. “Dominant” describes expression between alleles; it does not mean better, stronger or healthier.
Understanding by example
Under a simple complete-dominance model, AA and Aa may share one phenotype while aa differs. In an Aa × aa cross, each offspring has a one-half probability of being Aa and a one-half probability of being aa, although a small brood may not match that ratio exactly.
Common misconceptions
A dominant trait is not necessarily common or advantageous. Heterozygotes differ under incomplete dominance and codominance, so the label alone cannot place every morph into the same table. Confirm the inheritance model supported for the particular trait.
Related reading and sources
For species-specific context, see Inheritance Models Used for Reptile Morphs. Browse the full glossary.
Basic reference: NHGRI: Dominant.