Indian scientists have assembled the genome sequence of the poisonous Indian Cobra paving way for researchers to synthesise cost-effective and safe humanised anti-venom.
The research which was led by Somasekar Seshagiri from SciGenom Research Foundation (SGRF), Bengaluru, India, has been recently published in Nature Genetics.
Snakebite poisoning is a serious and neglected tropical disease that kills around 81 000 to 138 000 people annually. According to the WHO, over 5 million snake bites occur each year, resulting in about 2.7 million cases of envenomings and around three times as many amputations and other permanent disabilities every year.
In India, most of these deaths have been attributed to the so-called ‘big four’ deadly snakes — the Indian cobra (Naja naja), common krait (Bungarus caeruleus), saw-scaled viper (Echis carinatus) and Russell’s viper (Daboia russelli), resulting in over 46,000 estimated snakebite-related deaths each year.
Using genome–transcriptome analysis the researchers could identify 19 ‘venom-ome specific toxins’ (VSTs) from the genome of Indian cobra which is primarily expressed in the snakes’ venom glands.
To obtain the high-quality genome assembly the scientists had employed a variety of long-read and short-read sequencing technologies. Using gene expression data of tissues from 14 different cobras, the scientists could predict 23,248 protein-coding genes. Of these genes, 12,346 of the venom-gland-expressed genes were found to be ‘venom-ome’ and this comprised 139 genes from 33 toxin families which were responsible for production of the toxins- 19VSTs.
Researchers revealed that the identification of toxin genes, could facilitate the development of effective humanized anti-venom with a defined composition using recombinant technologies in the future.
Once the genomic sequences of other three poisonous snakes also get unveiled, say the researchers, that a broad anti-venom can be made by developing synthetic human antibodies against these toxins.
Using the high-quality genome mapping of Indian cobra, the scientists could also study various aspects of the snake venom biology, including venom gene genomic organization, genetic variability, evolution and expression of key venom genes.
Although anti-venoms are available currently, its composition is not well-defined as they are developed by immunising large animals like horses which may cause adverse immunological reactions in patients. Thus leveraging genomics in creating anti-venom can help create more efficacious solution to the snakebite envenoming, concludes the researchers.
Scientists from SGRF’s AgriGenome Labs and MedGonome Labs, US firm Genentech, Wayanad Wildlife Sanctuary in Kerala and their peers from many universities in the US and Singapore also participated in the study.