The apparent color is a physics trick, not a paint job. No blue dye exists. In a Husky iris, low melanin leaves stromal tissue able to scatter incoming light through Tyndall scattering, so short wavelengths return more strongly than longer ones. The surface reads blue. No pigment makes it blue.The genetic signal is unusually clean. A 98.6-kilobase duplication near ALX4, a developmental transcripti...More