Decoding Ancient Secrets — With Help from Kerala’s Forests

In a landmark global study, scientists have reconstructed the deepest branches of the amphibian Tree of Life, using genomic data from nearly 300 species across the world, and Kerala played a role in this scientific leap.

Published in Systematic Biology, the study combines data from over 220 nuclear genes of frogs, salamanders, and caecilians to resolve evolutionary relationships that have baffled biologists for decades. It provides compelling support for the idea that frogs and salamanders are each other’s closest relatives (the Batrachia hypothesis), leaving caecilians — the legless, worm-like amphibians — as their more distant cousins.

Why This Study Matters
Despite being one of the most diverse and ancient vertebrate groups, amphibians have long defied clean evolutionary categorisation. The study tackled this by using a new probe set tailored for amphibians, overcoming challenges like huge genome sizes (some salamanders have genomes over 100 times larger than humans!) and deep gene tree conflicts caused by rapid diversification over 250 million years ago.

Local Link: The Western Ghats in the Genomic Spotlight
One of the authors, Sandeep Das of Kerala Forest Research Institute, contributed vital samples from the Western Ghats, including the elusive Nasikabatrachus sahyadrensis — the Purple Frog — an ancient species that diverged from its closest relatives (Sooglossid frogs from the Seychelles) more than 60 million years ago.

This reinforces the Ghats’ position as a living museum of evolutionary history and underscores the biogeographic connection between India and ancient Gondwana.