A study at Peking University in China suggests that the pigmentation in white tigers is caused by a mutation of just one gene. The authors suggest that by locating the faulty gene, of which breeding tigers would each need one to create a white cub, they could increase the population of Indian tigers with selective breeding based on DNA testing.
Nevertheless, the white tiger population found only in captivity and suffering from several abnormalities thanks to generations of inbreeding is still not a separate subspecies and many believe hold no place in tiger conservation. And with fewer than 3,200 tigers left in the wild, it’s perhaps a distraction to worry about conserving this one mutant gene. As John Seidensticker of the Smithsonian Institution bluntly puts it, “We have much more pressing tiger conservation problems.”
Read this article by Ed Young: Tiger, Tiger, Burning Bright, Just One Gene To Make It White
The paper is published in Current Biology:
Xu, Dong, Hu, Miao, Zhang, Zhang, Yang, Zhang, Zou, Zhang, Zhuang, Bhak, Cho, Dai, Jiang, Xie, Li & Luo. 2013. The Genetic Basis of White Tigers. Current Biology. http://dx.doi.org/10.1016/j.cub.2013.04.054