The absence of the red and yellow pheomelanin pigments that ordinarily produce the orange hue accounts for a white tiger's pale coloring. The tyrosinase (TYR) gene mutation had long been thought to be the cause of this. A less severe mutation in the same gene in other mammals causes selective loss of pheomelanin, or the so-called Chinchilla characteristic, whereas a knockout mutation in this gene causes albinism, or the inability to produce either pheomelanin (red and yellow pigments) or eumelanin (black and brown pigments). ? 8? animal den white tiger plush ? Each piece on hang tag ? Soft, cozy plush material ?Features hard plastic eyes ? Sitting position ? Ideal keepsake ? One piece per unit Ages 3+ Brand New QTY:1