Scientists Sequence Genome of Indian Cobra

An international team of researchers has sequenced the genome of the Indian cobra (Naja naja), a highly venomous, medically important snake.

The Indian cobra (Naja naja). Image credit: Kamal N.V. / CC BY 3.0.

Accidental contact with venomous snakes can be deadly. Snakebite envenoming is a serious neglected tropical disease that affects 5 million people worldwide annually.

In India alone, the high rural population density combined with the presence of the ‘big four’ deadly snakes — namely the Indian cobra, the Russell’s viper, the saw-scaled viper and the common krait — results in 46,000 snakebite-related deaths annually.

“Snake venom, primarily used by the snake to subdue its prey, is a great source of drug-like molecules,” the scientists said.

“The genome of the Indian cobra is no exception, and it codes for toxin molecules that can block pain, reduce blood pressure and prevent blood clots.”

Using a number of genomic technologies, the study authors successfully sequenced the Indian cobra genome.

They identified 23,248 protein-coding genes, including 12,346 venom-gland-expressed genes that constitute the so-called ‘venom-ome.’

“The high-quality genome allowed to us study various aspects of snake venom biology, including venom gene genomic organization, genetic variability, evolution and expression of key venom genes,” they said.

Indian cobra’s minimal venom cocktail: 19 venom-ome-specific toxin genes (VSTs), accessory venom proteins (AVPs), and their primary physiological targets. ECM – extracellular matrix, PDIs – protein disulfide isomerases. Image credit: Suryamohan et al, doi: 10.1038/s41588-019-0559-8.

The team also identified a set of 19 venom-ome-specific toxin genes that constitute the core venom toxins.

“For the first time, we now have a full list of venom-relevant toxin genes of the Indian cobra,” said co-author Professor R. Manjunatha Kini, a scientist at the Department of Biological Sciences at National University of Singapore.

“We believe the Indian cobra reference genome and the analysis will facilitate innovations in antivenom development,” the researchers said.

“The genome and the associated predicted proteome will serve as a powerful platform for evolutionary studies of venomous organisms.”

“More importantly, the comprehensive catalog of the venom proteins should enable drug development, in particular to treat hypertension, pain and other disorders.”

The results are published in the journal Nature Genetics.

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K. Suryamohan et al. The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins. Nat Genet, published online January 6, 2020; doi: 10.1038/s41588-019-0559-8