Why in the news?
- Recently, a team of scientists has resolved the genetic mystery of Simlipal’s so-called black tigers.
- The Simlipal Tiger reserve is situated in Odisha.
- The study found that a single genetic mutation in these tigers caused black stripes to broaden or spread into the tawny background.
- Simlipal’s small and isolated tiger population led to inbreeding and the anomalous phenotype characterised by wide, merged stripes.
- The loss of genetic diversity is evident from the low heterozygosity — chances of inheriting different forms of a particular gene from each parent — in Simlipal (28%) compared to Central India (36%).
Characteristics of Tiger:
- Tigers have a distinctive dark stripe pattern on a light background of white or golden.
- A rare pattern variant, distinguished by stripes that are broadened and fused together, is also observed in both wild and captive populations. This is known as pseudo-melanism, which is different from true melanism, a condition characterised by unusually high deposition of melanin, a dark pigment.
- Inbreeding of such tiger populations will be subject to genetic drift (chance events), and inbreeding depression (decreased survival).
- Overall, such tiger populations have a high chance of extinction.