Grey in the Turquoise Parakeet
Grey is a straightforward autosomal dominant mutation: one copy is enough to fully express it, and a second copy doesn't change the look at all — both single- and double-factor birds are simply "Greygreen." The only reason zygosity still matters is breeding math: a double-factor Greygreen parent is guaranteed to pass a Grey allele to every offspring, while a single-factor parent only passes it half the time.
What is the Grey mutation?
Grey is logged in this calculator's reference data as a simple autosomal dominant structural mutation, producing a phenotype called Greygreen. This is true (simple) dominance, not the incomplete dominance seen in Dark Factor — a Grey bird with one copy looks exactly the same as a Grey bird with two. The equivalent "Dominant Grey" mutation is one of the most well-documented dominant mutations in parrot genetics generally, most famously in budgerigars, where it produces the classic Grey-Green and Grey varieties.
How it works, in plain terms
Like Dark Factor, Grey works on the same light-scattering structural layer that contributes to a bird's blue-green appearance, rather than adding or removing pigment directly. It mutes and flattens the bright wild-type green into a duller, more olive-mustard "Greygreen" tone. Because the gene is fully dominant, a single copy is enough to fully switch on this effect — there's no partial or intermediate look the way Dark Factor has with its Dark Green stepping stone.
Autosomal inheritance, explained
Grey sits on an ordinary autosome, so cocks and hens inherit and express it identically — no sex-linked wrinkle to account for.
Genotype → phenotype
| Genotype | Appearance | Applies to |
|---|---|---|
| G⁺ / G⁺ | Normal | Cocks & hens |
| G⁺ / G | Greygreen | Cocks & hens |
| G / G | Greygreen (visually identical to single-factor) | Cocks & hens |
Sources & honesty note
The inheritance type, symbol, and category for Grey in Neophema Pulchella come from this calculator's own compiled reference library. The plain-language explanation of dominant structural mutation above draws on well-established, cross-species psittacine genetics (the equivalent Dominant Grey mutation is extensively documented in budgerigars); it has not been verified line-by-line against Neophema-pulchella-specific photographs. See the full references page for this project's other sources.