FAQ

Multi-locus Compounds

Some named morphs are not a single trait. They are the visual combination of two genes that happen to look distinctive together — a phenotype the breeder community gave a name to, even though there's no single allele that makes them.

The four canonical examples:

  • Sunglow (Boa Constrictor) = Albino (recessive) + Hypo (codominant)
  • Snow (Corn Snake) = Amelanistic (recessive) + Anerythristic (recessive)
  • RAPTOR (Leopard Gecko) = Tremper Albino (recessive) + Eclipse (recessive)
  • Blizzard (Leopard Gecko) = Murphy Patternless (recessive) + Tremper Albino (recessive)

A Sunglow Boa is genetically a homozygous Albino plus at least one copy of Hypo. The "Sunglow" label describes the look, not a separate gene.

Why these can't be a single trait in the catalog

If you list Sunglow as a "single recessive trait" with the rest of the recessives, the calculator breaks predictably. A Sunglow × Sunglow cross would predict 100% Sunglow babies — but in reality, those babies follow Mendel on two separate loci:

  • Albino × Albino → 100% visual Albino ✓
  • Hypo × Hypo → 25% Super Hypo + 50% Hypo + 25% normal

A "Sunglow" baby is one that's both visual Albino and at least het Hypo. That's not a single number you can predict cleanly without modelling the underlying two genes.

How the catalog handles them

For each of the four compounds, the catalog has a combo entry with inheritance marked unknown. The entry points at its components (Albino + Hypo for Sunglow):

  • The Sunglow entry has unknown inheritance, linked to Albino + Hypo as components.
  • When the calculator sees unknown, it returns the honest note: "outcomes vary — modelled as a multi-locus compound." No invented percentages.
  • When you breed and the calculator runs on the underlying Albino + Hypo traits (which the parents carry separately), it produces correct per-locus predictions.

This means: don't pick "Sunglow" as the trait on a Sunglow boa. Pick Albino visual + Hypo visual instead. The Sunglow combo entry exists for catalog browsing and historical-record purposes, but the calculator works correctly only when the parents carry the underlying components as separate traits.

That's a real ergonomic compromise. The plan to make multi-locus compound names work end-to-end (you pick "Sunglow" and the form automatically splits it into Albino + Hypo) is on the roadmap but not built today.

Single-locus vs multi-locus — the contrast

A common confusion. Compare with Allelic complexes:

| | Single-locus compound | Multi-locus compound | |---|---|---| | Mechanism | Two alleles at one gene | Two genes interacting | | Example | BEL (any two BluEL alleles) | Sunglow (Albino + Hypo) | | Calculator | Punnett via the locus engine — gives clean percentages | Marked unknown, returns "outcomes vary" | | Catalog entry | Two separate traits sharing a locus | One combo entry pointing at the components | | Saved as | Two traits on the animal | The combo entry |

A BEL is one animal with two BluEL traits (Mojave + Lesser, or whichever). A Sunglow is one animal with two traits from two different loci (Albino + Hypo). Both look like "two traits on the animal," but the mechanism is different — and it shows up the moment you breed them.

What's NOT in the multi-locus list

Some morphs the community sometimes describes as "compound" are not multi-locus in the catalog:

  • Killer Bee (Pastel + Spider) — these are independent codominants. The calculator predicts them correctly by working out Pastel and Spider separately and combining them. The "Killer Bee" name is shorthand for the visual combo, but neither parent locus is special — it's just visual Pastel AND visual Spider. No combo entry needed.
  • Bumble Bee (Pastel + Spider) — same shape as Killer Bee.
  • Spider Pied — Spider (dominant) + Piebald (recessive visual). Same — independent loci.

The list of four (Sunglow, Snow, RAPTOR, Blizzard) is the set where treating them as a "single trait" would produce wrong calculator predictions. Killer Bee × Killer Bee gives the correct answer by computing Pastel × Pastel and Spider × Spider independently and combining — no combo entry needed.

Known gap: Salmon Glow

Salmon Glow is the Boa Constrictor compound of Salmon (a Hypo synonym) + Albino — same shape as Sunglow, just with the Salmon line of Hypo. It is not in the catalog today. Adding it would be the same shape as Sunglow: a combo entry pointing at Salmon + Albino with unknown inheritance.

Similar gaps may exist for Diablo Blanco (RAPTOR + Murphy Patternless? evidence shaky) and other named multi-locus combos. Until the calculator learns to surface multi-locus compound names end-to-end, adding more of these would just mean more entries that emit "outcomes vary." So the catalog ships only the four where the name is established and the underlying components are non-controversial.

For the per-species coverage of what is and isn't included, see Catalog and the species page (e.g. Boa Constrictor).