Rare Mutation in Black Tiger

In News

• Researchers from the National Centre for Biological Sciences (NCBS) have zeroed in on a rare mutation that results in large, merged stripes that cause the tiger to appear black in Similipal Tiger Reserve (STR).

About

• The rare mutation behind this has been found in Transmembrane Aminopeptidase Q or Taqpep gene.
• The main cause of the rare mutation is genetic drift. Due to this geographic isolation, genetically related individuals have been mating with each other for many generations in Similipal, leading to inbreeding.
• The Similipal Tiger Reserve (STR) is the only tiger habitat in the world with melanistic tigers, which have broad black stripes running across their bodies and are thicker than those seen on normal tigers.

Black Tigers

• They are a rare colour variant of the tiger and are not a distinct species or geographic subspecies.
• The abnormally dark or black coat in such tigers is termed pseudomelanistic or false coloured.
• The only other black tigers outside of Similipal in India exist at the Nandankanan Zoological Park in Bhubaneswar, Ranchi Zoo and Chennai’s Arignar Anna Zoological Park.
• If you pick any tiger from Similipal, the chance that it carries the mutant gene is almost 60 per cent.
• The darker coat colour of the mutants offers them a selective advantage when hunting in the dense closed-canopy and relatively darker forested areas of Similipal as compared to the open plains of most other tiger habitats.

Similipal Biosphere Reserve

• It is one of the largest biospheres in India. It is a national park and a tiger reserve as well.
  • It derives its name from ‘Simul’ (silk cotton) tree.
  • It was declared a biosphere reserve by the Government of India in June 1994.
• Location: 
  • It lies in the eastern end of the eastern ghat and is located in the northern part of Odisha’s Mayurbhanj district.
• Spread: 
  • It is spread over 4,374 sq. km, out of which 845 sq. km. is core forest (tiger reserve), 2,129 sq km is the buffer area and 1,400 sq km is transition space.
• Flora:
  • It boasts of having tropical semi-evergreen forests, tropical moist deciduous forests, dry deciduous hill forests, high-level sal forests and sprawling meadows.
  • Sal is a dominant tree species.
• Fauna:
  • It is home to a wide range of wild animals including mammals like tigers and elephants, besides species of birds, amphibians and reptiles, all of which collectively highlight the biodiversity richness of Similipal.
• It also houses melanistic tigers which are found only in Odisha.

Source: IE