Understanding Reptile Morph Genetics

Morph genetics determine the visual appearance of offspring. Understanding inheritance patterns is essential for planning profitable pairings.


Inheritance modes:

  • Recessive: Both parents must carry the gene for it to appear visually. Visual x visual = 100% visual offspring. Het x het = 25% visual, 50% het, 25% normal.
  • Co-dominant: One copy produces a visible phenotype, two copies produce a "super" form. Pastel x Normal = 50% Pastel, 50% Normal. Pastel x Pastel = 25% Super Pastel, 50% Pastel, 25% Normal.
  • Dominant: One copy shows the full trait. The super form looks identical or very similar.

    • Common ball python recessive morphs: Clown, Pied, Axanthic, Genetic Stripe, Desert Ghost, Ultramel


    Common ball python co-dominant morphs: Pastel, Fire, Yellowbelly, Enchi, Mojave, Lesser/Butter, Cinnamon


    Multi-gene crosses:

    Probabilities for independent genes multiply. If Gene A has a 50% chance and Gene B has a 25% chance, the probability of both appearing together is 12.5%.


    Proving out hets:

    Breed a suspected het to a known visual. If any visual offspring appear, the parent is confirmed het. One clutch with no visuals does not disprove het status — it only reduces the probability.

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