Studies on a plumage mutant (black at hatch) in the Japanese quail

Morphological, genetical and developmental studies were performed on a mutant, Black at hatch (Bh), in the Japanese quail. (1) In newly hatched Bh-type chicks, there was intermingling of black and yellow pigments in the dorsal down feathers. In the Bh-type adult feathers, yellow and black bands on the webs were narrow and large in number. Some feathers are devoid of these bands and show intermediate colouration between black and yellow. (2) Genetical analysis has shown that the Bh-character is controlled by an autosomal dominant gene with homozygous lethality and that there are no linkage between Bh-locus and the other four autosomal loci, Y (yellow), W (white), S (silver) and we (white egg-shell). (3) Embryological investigation has demonstrated that the homozygous embryos for Bh-gene die at 4-6 days of incubation, showing whole body haemorrhage, degeneration of liver tissue, less well-developed eyes and occasionally less well-developed limbs and tails.