White Tiger Unique Coat: A Result of One Genetic Mutation

Since their discovery in the Indian jungle centuries ago, white tigers, a variant of Bengal tigers have left scientists wondering how they get their unique coat.

Scientists at Peking University, writing in the journal Current Biology, say the Bengal tigers white coats are produced by a single change in a known pigment gene. A recessive trait will only show up if the individual gets two genes for that trait, one each from mom and dad.

"The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving, but is now seen only in captivity," says Shu-Jin Luo of China's Peking University who was a lead author in the study published in Current Biology.

The researchers mapped the genomes of a family of 16 tigers living in Chimelong Safari Park, including both white and orange individuals. They then sequenced the whole genomes of each of the three parents in the family.

The study noted that the genetic variant found in the white tiger prevents the creation of red and yellow pigments but has little to no effect on black, which explains why white tigers still show characteristic dark stripes.

"The last known free-ranging white tiger was shot in 1958, before which sporadic sightings were made in India," the researchers write.

"Reasons for the extinction of wild white tigers were likely the same as those accounting for the dramatic decline in wild tigers in general: uncontrolled trophy hunting, habitat loss, and habitat fragmentation.

"However, the fact that many white tigers captured or shot in the wild were mature adults suggests that a white tiger in the wild is able to survive without its fitness being substantially compromised."