Psittacula eupatria & Psittacula krameri: the fivefold SL ino (Lutino) mystery
24/03/2026
Five genetically distinguishable SL ino mutations. One identical Lutino phenotype. How NeorniLab tells them apart with DNA analysis.
Not all yellow is the same.
All lutinos look alike. Pale yellow plumage, red eyes, yellow flight feathers. Yet their genes tell a different story.
In the Alexandrine Parakeet (Psittacula eupatria) and the Rose-ringed Parakeet (Psittacula krameri) we have, to date, mapped five genetically distinguishable SL ino mutations, each at a different position in the same gene, and each with its own story. Visually one picture, genetically five.
How many lutino mutations exist in the Alexandrine and Rose-ringed Parakeet?
A lutino arises because an enzyme that produces eumelanin (the dark pigment) is disrupted, while the psittacofulvin (the yellow-red pigment) remains intact. The result is visually identical across all five SL ino mutations: a yellow bird with red eyes. Genetically, by contrast, they are five independent genotypic variants, each at a different position in the gene. Only a DNA analysis can tell them apart.
Inheritance
All five SL ino mutations are inherited sex-linked recessive. The "SL" in the name refers to sex-linked: the mutation sits on the Z sex chromosome.
In birds, the sex-chromosome pattern is the reverse of mammals:
- Males are ZZ. They need two copies of the mutation to be phenotypically lutino. A male carrying only one copy is split (a carrier without outward expression).
- Females cannot be split for SL ino mutations. They have only one Z chromosome and therefore automatically carry just one copy of an SL ino mutation. As a result they are either lutino or completely free of it. This also applies to other sex-linked mutations.
The five SL ino mutations at a glance
We number the ino mutations in the Psittacula eupatria and the Psittacula krameri continuously, in order of discovery and because the two species have become genetically strongly intertwined. All five mutations, when homozygous, produce the classic lutino phenotype.
- SL ino1. This genotypic variation we have so far picked up only in the Psittacula eupatria. Some breeders consider SL ino1 the only "true eupatria ino". Genetically we cannot substantiate that; we can only say that we have to date established SL ino1 exclusively in this species.
- SL ino2. Occurs in both the Psittacula eupatria and the Psittacula krameri, at exactly the same position in the gene. That cannot be coincidence. We come back to it at length in our blog post on species purity.
- SL ino3. So far we have found this mutation only in the Psittacula krameri. Should SL ino3 ever turn up in a Psittacula eupatria, that may point to crossing-in. With the current data, however, we cannot fully rule out that the mutation also arose spontaneously in the Psittacula eupatria.
- SL ino4. Likewise found only in the Psittacula krameri so far. Same caveat as for SL ino3.
- SL ino5. A new genotypic variant that we are currently working out further. Identified in an Italian bloodline, to date only in the Psittacula eupatria. Confirmation will follow soon.