title: The genetic basis of white tigers.
abstract: The white tiger, an elusive Bengal tiger (Panthera tigris tigris) variant with white fur and dark stripes, has fascinated humans for centuries ever since its discovery in the jungles of India. Many white tigers in captivity are inbred in order to maintain this autosomal recessive trait and consequently suffer some health problems, leading to the controversial speculation that the white tiger mutation is perhaps a genetic defect. However, the genetic basis of this phenotype remains unknown. Here, we conducted genome-wide association mapping with restriction-site-associated DNA sequencing (RAD-seq) in a pedigree of 16 captive tigers segregating at the putative white locus, followed by whole-genome sequencing (WGS) of the three parents. Validation in 130 unrelated tigers identified the causative mutation to be an amino acid change (A477V) in the transporter protein SLC45A2. Three-dimensional homology modeling suggests that the substitution may partially block the transporter channel cavity and thus affect melanogenesis. We demonstrate the feasibility of combining RAD-seq and WGS to rapidly map exotic variants in nonmodel organisms. Our results identify the basis of the longstanding white tiger mystery as the same gene underlying color variation in human, horse, and chicken and highlight its significance as part of the species' natural polymorphism that is viable in the wild.
authors.affiliation: Peking-Tsinghua Center for Life Sciences, Laboratory of Genomic Diversity and Evolution, College of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Xu
authors.forename: Gui-Xin
authors.initials: GX
authors.lastname: Dong
authors.forename: Xue-Song
authors.initials: XS
authors.lastname: Hu
authors.forename: Lin
authors.initials: L
authors.lastname: Miao
authors.forename: Xue-Li
authors.initials: XL
authors.lastname: Zhang
authors.forename: De-Lu
authors.initials: DL
authors.lastname: Zhang
authors.forename: Han-Dong
authors.initials: HD
authors.lastname: Yang
authors.forename: Tian-You
authors.initials: TY
authors.lastname: Zhang
authors.forename: Zheng-Ting
authors.initials: ZT
authors.lastname: Zou
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Jong
authors.initials: J
authors.lastname: Bhak
authors.forename: Yun Sung
authors.initials: YS
authors.lastname: Cho
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Dai
authors.forename: Tai-Jiao
authors.initials: TJ
authors.lastname: Jiang
authors.forename: Can
authors.initials: C
authors.lastname: Xie
authors.forename: Ruiqiang
authors.initials: R
authors.lastname: Li
authors.forename: Shu-Jin
authors.initials: SJ
authors.lastname: Luo
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D005260:Female; D055106:Genome-Wide Association Study; D006197:Hair / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010858:Pigmentation; D011110:Polymorphism, Genetic; D046010:Tigers / Q000235:genetics* / Q000378:metabolism
chemical_list: D026901:Membrane Transport Proteins