As researchers have previously warned, Tigers in India may be a little too close for comfort -- when it comes to their DNA, anyway.
A new study from Cardiff University has researchers concerned that Indian tigers face extinction because of a lack of "genetic diversity."
Partnering with India's National Center for Biological Sciences, researchers compared current DNA samples from tigers on the Indian subcontinent to genetic data obtained during the time of the British Raj, a period of British rule in India from 1858 to 1947. They found that 93 percent of the tiger DNA variants from that historical period are no longer present in the current tiger population.
"This is due to loss of habitat and habitat fragmentation, meaning lower population sizes, and the prevention of tigers from dispersing as they once would have, which means their gene pool is no longer mixing across the subcontinent," Mike Bruford, a professor at the Cardiff School of Biosciences, explained to the BBC.
The lack of genetic diversity in Indian tigers presents an obvious "red flag" for conservationists, Bruford and his team note in the study.
Genetic variation can be crucial for species survival and adaptation to environmental change, and its judicious management is now required in the Convention on Biological Diversity’s 2020 targets. Although recent studies demonstrate that Indian tigers retain the highest proportion of the species’s genetic variation, this study demonstrates that some components of that genetic variation have been lost, and what remains is now subdivided.
Though conservation efforts -- from protected reserves to endeavors to mitigate human-tiger conflict -- are currently in place, researchers state that "it is critical to maintain within-population variation, as well as increasing population connectivity" on a large scale.
While the study's findings are startling, researchers warned in 2011 that poor genetic diversity may be a threat to the tiger population. That year, a Wildlife Institute of India study revealed a loss of many alleles -- an alternate form of a gene, which can cause varying characteristics across a species -- among tigers in the Ranthambore Tiger Reserve. At the time, investigator S. P. Goyal attributed the loss to "an isolated population without any genetic exchange," according to the Times News Network.
The tiger is classified as endangered on the International Union for Conservation of Nature's Red List of Threatened Species. According to the World Wildlife Fund, the tiger population is estimated to be as low as 3,200, with as few as 1,400 tigers in India.