What is the “odd eye” gene?

There are two main contexts in which odd-eye can occur:

🐾 1. White cats (W gene)
The W (dominant white) gene masks all coat colors and can influence eye color.
Cats with the WW or Ww genotype are completely white.
In this case, expression of the W gene may result in one blue eye or both eyes being blue, and sometimes odd-eye.
⚠️ The W gene can also be associated with deafness.

🐾 2. Cats with white spotting (S gene)
Bicolor cats or cats with a large amount of white can be odd-eyed even if they are not entirely white, especially when the white pattern affects the head.
The more extensive the white spotting, the higher the likelihood of blue eyes or odd-eye.

🐾 And in Selkirk Rex or Devon Rex cats?
Selkirk Rex and Devon Rex cats can carry either the white gene (W) or the white spotting gene (S). Odd-eye is therefore possible, particularly in:

🐾 White cats
🐾 Bicolor cats with a large amount of white on the head