Light Down

Light down is an incomplete dominant mutation in coturnix quail that changes the plumage slightly in heterozygous form, but creates an almost all cream colored bird in homozygous form (1). About 1/3 of the homozygous chicks die before they can hatch, and those that do hatch present extreme neurological issues and don't survive longer than a week (2).

The gene, originally discovered in Japanese labs in 1993, presents very similar to Calico in heterozygous form. With only one copy, the bird will be slightly lighter overall, with a whiter breast and face, and slightly wider striations across the back. There also is an increase in horizontal barring across the feathers (2).

However, in homozygous form, the bird is almost entirely a light cream color, with very little down patterning coming through, similar to Silver and Andalusian (2). They also will have larger pupils and smaller iris, and likely some vision issues. The cognitive issues vary from bird to bird, with the most mild being slight head shaking and the most extreme

being unable to put their head down, and rolling forward or drawing backwards to be able to move (1). This is believed to be caused by inner ear canal or brain issues associated with the gene (2).

It is not currently believed to be in public hands at this time. The gene symbol is ldl, and the order of dominance is Light Down > Wildtype.

Breeding with Light Down:

Wildtype x Light Down = 50% Wildtype, 50% Light Down

(ldl+/ldl+ x Ldl/ldl+ = 50% ldl+/ldl+, 50% Ldl/ldl+)

Light Down x Light Down = 25% Wildtype, 50% Light Down, 25% Cream

(Ldl/ldl+ x Ldl/ldl+ = 25% ldl+/ldl+, 50% Ldl/ldl+, 25% Ldl/Ldl)

Note: Cream birds are usually sterile and cannot be bred if they survive to maturity)