In what groups we can divide the Bengal Tiger?

[Rishi]

Isolated Ranthambhore tigers are an unique genepool
Dec 5, 2017, 06:35 AM | IST

*This image is copyright of its original author

JAIPUR: Tigers of Rajasthan are a unique lot. Due to their seclusion from the remaining population in the country, as the tigers in the intermediate forests have withered away, the tigers in Ranthambhore and Sariska Tiger reserves have become genetically isolated.
On top of that, poaching had reduced their numbers to a mere dozen twice.

Through this, the threat of inbreeding and thereby extermination of these felines from the state becomes a real one. A study conducted by the Wildlife Institute of India (WII) and other agencies throws light in this regard, however, there appears to be a slight aberration as well.

Tigers in Rajasthan from the western most extant population of wild tigers. Historically, the range of these striped felines extended to northwest into Pakistan, but as population expand and the forested plains wee cleared for cultivation, they got locally extinct. Thus tigers in Ranthambhore and Sariska form the western most boundary.

The study says, “Our analyses reveal that tigers from the North-West cluster (Ranthambore) are genetically isolated. Such genetic isolation is supported by the fact that they form a distinct cluster in structure analysis and have the highest pair-wise with other genetic clusters.”
Furthermore, the study reveals that the tigers could be at high risk of extinction. “Data also suggest that genetic diversity in Ranthambore is much lower in comparison to all other genetic clusters, possibly due to small effective size and/or isolation. Low genetic variation contributes to higher extinction risk in wild populations. The results suggest that the Ranthambore population is isolated and that inbreeding depression is a realistic possibility in this population,” the study says about Ranthambhore tigers.

Logic dictates that when the gene pool shrinks, extinction of a specie become imminent. However there is a surprise hidden in Ranthambhore tigers too. They seem to be unperturbed, even through they are genetically isolated.

“They are separate from other individuals in the network analysis, even at low thresholds of genetic similarity,” the study reads. This means that even though Ranthambhore tigers are isolated, contrary to popular scientific belief, there is still a greater dissimilarity between tigers here.
“Tigers in Rajasthan have become unique and it is surprising that even after inbreeding no deficiency of any sort can be seen in these tigers. These tigers have adapted themselves to the arid zone and as the study reveals, are different from other tigers,” says Yadvendra Jhala of the WII.
Jhala further adds, “With genetic pool limitations come the threat of extinction but these tigers are surprisingly healthy. There is no malformation in them, yet.”
Reply