The enigma of the black tigers has been solved, according to a study published in the journal Proceedings of the National Academy of Sciences. Researchers discovered an uncommon mutation that resulted in the stripes merging and becoming darker in color.
The research team, led by Dr. Uma Ramakrishnan of the National Centre for Biological Sciences (NCBS), discovered the unique mutation accountable for this in a single gene called Transmembrane Aminopeptidase Q, or Taqpep. They were able to uncover results through genome sequencing across the tiger range, which led them in discovering this rare mutation in the Simlipal Tiger Reserve.
"Ours is the first and only study to investigate the genetic basis for this phenotype (look). While the phenotype has been talked about and written about earlier, this is the first time its genetic underpinnings were scientifically investigated," said Ramakrishnan, professor at NCBS.
Pseudomelanistic in nature
Several other species of cats, including cheetahs, have been reported to exhibit comparable shifts in coat color due to other mutations in this gene. The findings indicate that these tigers are Pseudomelanistic, with broad, merging stripes caused by genetic drift.
According to the researchers, the pattern change is triggered by a change in the genetic material's DNA Alphabet from C (Cytosine) to T (Thymine) at position 1360 of the Taqpep gene sequence. Dr. Ramakrishnan stated, "It is remarkable that we were able to identify the genetic foundation for such a dramatic pattern phenotypic in wild tigers, and even more intriguing that this genetic variant is at high frequencies in Similipal."
Years ago, scientists conducted numerous studies to determine the precise cause of this coloring. They even assumed they were natural accidents. Debabrata Swain, member secretary of the National Tiger Conservation Authority, stated in 2017 that "a combination of intense rainfall, rising temperatures, and rising humidity may have contributed in the melanistic mutation of Similipal tigers."
Black tigers are prone to extinction
At least for the time being, these black tigers have not been discovered in locations other than those already known. The last sightings of these tigers occurred in 2017 and 2018. Outside of Similipal, the only other black tigers in India are found at Bhubaneswar's Nandankanan Zoological Park, Ranchi Zoo, and Chennai's Arignar Anna Zoological Park, where they were born in captivity.
45 black tigers were reported in 2006, according to the Wildlife Conservation Society. Now, the Simlipal and Satakosia reserves in Odisha are down to just 28. According to SS Srivastav, the chief wildlife.