<p>White tigers, though uncommon, are perfectly natural as their yellow and black stripe cousins, Asian researchers have claimed rejecting an earlier theory that Royal Bengal Tigers turn white due to a genetic defect. <br /><br /></p>.<p>The elusive tiger with white fur, dark stripes, pink paws, pink nose and blue eyes was once seen sporadically in India. They survived for 300 years but became extinct due to game-hunting and habitat loss. The last one was shot in 1958.<br /><br />For close to four decades scientists believed that Royal Bengal Tigers turned white due to albinism–absence of the skin pigment melanin. They thought it was similar to “albino”, a disorder caused by a defect in the genes. <br /><br />Mapping the genomes of a family of 16 tigers living in Chimelong Safari Park in China, including white and orange varieties, a team of Chinese and South Korean researchers have dispelled the earlier notion.<br /><br />They could not spot “albino” genes but stumbled upon a new genetic mechanism which suggests that the spectacular white coats are produced by a single change in a known pigment gene.<br /><br />The genetic analysis led the researchers to a pigment gene SLC45A2, which had already been associated with light colouration in modern Europeans and in other animals, including mouse, horse, chicken and medaka fish. <br /><br />The variant found in the white tiger primarily inhibits the synthesis of red and yellow pigments but has little to no effect on black, which explains why white tigers still show characteristic dark stripes.<br /><br />“The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving, but is now seen only in captivity,” Shu-Jin Luo of China’s Peking University said. The findings have been published in the journal Current Biology on Thursday.<br /><br />The scientists claim, since white-skinned tigers were as natural as the yellow ones, that they could be conserved in the wild. <br /><br />It is worth considering because the tiger’s chief prey, such as deer, are also colour-blind.<br />The fact that many white tigers were hunted as mature adults suggests that they were fit to live in the wild. <br /><br />Records maintained by the Indian Tiger Welfare Society suggests that between 1920 and 1930s, as many as 15 white tigers were killed in Bihar as prized trophies, many of which are decorating museums in the UK and India.<br /><br />Historical records of white tigers on the Indian subcontinent date back to the 1500s. But the most famous white tiger was Mohan, a male captured in Rewa in Madhya Pradesh, from which numerous white tigers were bred for captivity Scientists said captive white tigers sometimes do show abnormalities, such as crossed eyes. <br /><br />But those frailties may have been caused due to inbreeding. After identifying the causal gene, the researchers plan to explore the evolutionary options that have maintained tigers in both orange and white varieties.</p>
<p>White tigers, though uncommon, are perfectly natural as their yellow and black stripe cousins, Asian researchers have claimed rejecting an earlier theory that Royal Bengal Tigers turn white due to a genetic defect. <br /><br /></p>.<p>The elusive tiger with white fur, dark stripes, pink paws, pink nose and blue eyes was once seen sporadically in India. They survived for 300 years but became extinct due to game-hunting and habitat loss. The last one was shot in 1958.<br /><br />For close to four decades scientists believed that Royal Bengal Tigers turned white due to albinism–absence of the skin pigment melanin. They thought it was similar to “albino”, a disorder caused by a defect in the genes. <br /><br />Mapping the genomes of a family of 16 tigers living in Chimelong Safari Park in China, including white and orange varieties, a team of Chinese and South Korean researchers have dispelled the earlier notion.<br /><br />They could not spot “albino” genes but stumbled upon a new genetic mechanism which suggests that the spectacular white coats are produced by a single change in a known pigment gene.<br /><br />The genetic analysis led the researchers to a pigment gene SLC45A2, which had already been associated with light colouration in modern Europeans and in other animals, including mouse, horse, chicken and medaka fish. <br /><br />The variant found in the white tiger primarily inhibits the synthesis of red and yellow pigments but has little to no effect on black, which explains why white tigers still show characteristic dark stripes.<br /><br />“The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving, but is now seen only in captivity,” Shu-Jin Luo of China’s Peking University said. The findings have been published in the journal Current Biology on Thursday.<br /><br />The scientists claim, since white-skinned tigers were as natural as the yellow ones, that they could be conserved in the wild. <br /><br />It is worth considering because the tiger’s chief prey, such as deer, are also colour-blind.<br />The fact that many white tigers were hunted as mature adults suggests that they were fit to live in the wild. <br /><br />Records maintained by the Indian Tiger Welfare Society suggests that between 1920 and 1930s, as many as 15 white tigers were killed in Bihar as prized trophies, many of which are decorating museums in the UK and India.<br /><br />Historical records of white tigers on the Indian subcontinent date back to the 1500s. But the most famous white tiger was Mohan, a male captured in Rewa in Madhya Pradesh, from which numerous white tigers were bred for captivity Scientists said captive white tigers sometimes do show abnormalities, such as crossed eyes. <br /><br />But those frailties may have been caused due to inbreeding. After identifying the causal gene, the researchers plan to explore the evolutionary options that have maintained tigers in both orange and white varieties.</p>
