Context

A group of researchers has discovered the genetic mutation that caused pseudomelanism in a limited number of tigers found only in the fourth largest tiger habitat in the country.

The rare Black Tiger

• The rare tigers were first officially discovered in STR in 2007. Since then it has been a mystery.
• These Odisha tigers essentially have stripes that are larger than found in other tigers. 
• And, these stripes merge among one another, causing the tigers to appear as though they have black-coloured skin.

Key-findings

• They found the black tigers are mutants and are Bengal tigers with a single base mutation in the gene Transmembrane Aminopeptidase Q (Taqpep).
• Different mutations in this gene are known to cause similar changes in coat colour in several other species of cats, including cheetahs.
• The drastic change in patterning and colouring of the black tiger's coat is caused by just one change in the genetic material DNA Alphabet from C (Cytosine) to T (Thymine) in position 1360 of the Taqpep gene sequence.
• Further genetic analyses and comparisons with a total of 395 captive and wild Indian tiger populations indicates that the mutation in Similipal tigers is very rare.
• The only other black tigers outside of Similipal in India exist at the 
  • Nandankanan Biological Park, Bhubaneswar
  • Arignar Anna Zoological Park, Chennai
  • Bhagwan Birsa Biological Park, Ranchi
• Genetic tracing proved that these captive-born tigers shared a common ancestry with Similipal tigers.