Hyderabad:Despite the Similipal National Park in Odisha, a sprawling tiger reserve and among the largest in India, the tiger population is estimated at 15 adults and six cubs. According to a joint study conducted by a team in India and the US — Proceedings of the National Academy of Sciences (PNAS) of the United States of America — geneticists have identified over one-third of the tigers in the Similipal Tiger Reserve are pseudomelanistic. Pseudomelanistic tigers look mostly black, hence their nickname of “black” tigers.
Incidentally, the Similipal Tiger Reserve is home to probably the only pseudomelanistic ‘black’ tigers in the world. Pseudomelanism is a rare genetic trait in tigers whose thick stripes are packed together such that the orangish-brown background is barely visible between the stripes, making it appear black.
Senior Congress leader Jairam Ramesh in his several tweets drew attention to the declining number of tigers: "Simlipal in Odisha is a sprawling tiger reserve, amongst the largest in India. Its tiger population is estimated at 15 adults & 6 cubs. Pathetically low! Not only that, a recent research paper shows it’s home to probably the only pseudomelanistic ‘black’ tigers in the world."
In his earlier tweet, Ramesh explained: "Pseudomelanism is a rare genetic trait in tigers whose thick stripes are packed together such that the orangish-brown background is barely visible between the stripes, making it appear black."
Further, the National Centre for Biological Sciences (NCBS) in Bangalore found a significant presence of pseudomelanistic ‘black’ variant in the tiger population of Similipal. Genetic analyses confirm that the tiger reserve has a small, genetically impoverished population & they face a higher risk of extinction.
Similipal National Park is a national park and a tiger reserve in the Mayurbhanj district (Odisha) spread over 2,750 km is also home to Bengal tiger, Asian elephant, gaur, and chausingha. This protected area is part of the UNESCO World Network of Biosphere Reserves since 2009.
Ramesh went on to urge: "Improving the genetic pool of the tigers, protection of the ‘black’ tigers and increasing the overall tiger population in the Simlipal Tiger reserve requires urgent measures and constant monitoring from both @moefcc and the Govt of Odisha."
What Causes Pseudomelanism in Tigers?
Pseudomelanism in tigers is inherited as an autosomal recessive trait as predicted from the captive pseudomelanistic tigers' pedigree. Our analyses of the genomes of eight captive tigers (three pseudomelanistic) from NKB revealed that all the pseudomelanistic tigers were homozygous for a single nucleotide variant predicted to alter a conserved and functionally important residue in the Taqpep gene... We observed a single base substitution in exon nine from C to T at position 1360 (Taqpep c.1360C > T), which translates into a missense mutation at position 454 (histidine to tyrosine) in the primary sequence (National Center for Biotechnology Information of the protein (Taqpep p.H454Y)... We observed no other nonsynonymous substitutions in Taqpep that segregate with pseudomelanism. We genotyped noninvasive samples of eight additional individuals related to the pseudomelanistic tigers from NKB and five individuals (two pseudomelanistic) from AAC at the Taqpep c.1360C > T variant site and observed complete concordance of Taqpep p.H454Y with pseudomelanism. Loss-of-function mutations in Taqpep in other felid species (different positions) result in similar pattern variants, providing strong evidence for causality. (Courtesy: PNAS)
