Description:
Panda is a gene in coturnix quail that is similar to dotted white in that it causes the bird to present with almost a tuxedo-like or white-winged-pied type pattern (1). However, it is different than both in that it is entirely recessive (1). It is also similar but separate from splash in the markings that it throws (2).
With two copies of the gene, panda creates an almost all-white bird, with two big patches of color across the back of the head and back of the body (3). This color will match the underlying base color and any additional dilutions. For example, if the panda gene is bred into a silver fawn quail, the two patches of color will be a light grey with basic fawn patterning (2).
It is easy enough to distinguish natural panda from natural english white even at hatch from the positioning of the colored patches (2). Whereas english white will have a single, small colored dot on the back of its head, panda will have two separate splotches of color. It also naturally has significantly less color than splash or white winged pied. It is important to note majority of the white genes can be bred to look like one another (for example, it is completely possible to breed an english white to eventually have increased color markings until it looks like the panda gene), however it doesn't change the underlying gene itself, and that english white can never "turn into" the panda gene. Panda will always be recessive (1).
The panda gene is found most often in laboratories abroad, including in France and Asia (3). It is unknown how common it is in backyard flocks, and is not currently believed to be in public hands in the United States. It also has been shown to have decreased growth patterns when compared to english white, though whether that is because of the lineage or because of the gene itself is unknown (4).
Breeding with Panda:
Panda x Panda = 100% Panda
Panda x Wildtype = 100% Panda Splits
Panda x Panda Split = 50% Panda, 50% Panda Split
Panda Split x Panda Split = 25% Panda, 50% Panda Split, 25% Wildtype
Panda Split x Wildtype = 50% Panda Split, 50% Wildtype
References & Further Reading
Miwa, M., et al. "Endothelin receptor B2 (EDNRB2) is associated with the panda plumage colour mutation in Japanese quail." Animal genetics 38.2 (2007): 103-108.
Tsudzuki, M., et al. "Allelism of panda and dotted white plumage genes in Japanese quail." Journal of Heredity 84.3 (1993): 225-229.
Mizutani, Makoto, et al. "Genetic analysis of a new plumage-pandain Japanese quail." Exp. Anim. 23 (1974): 59-61.
Nwaogwugwu, U. C., O. M. Obike, and U. H. Udoh. "Comparative evaluation of egg production and egg quality characteristics of panda white and cinnamon brown strains of Japanese quail." International Journal of Agriculture and Rural Development 21.1 (2018): 3534-3540.
Ito, Shin-ichi, Masao Kimura, and Iwahiro Isogai. "Linkage between panda plumage and albumin loci in Japanese quail." Japanese Journal of Zootechnical Science 59 (1988): 822-824.