A team based at the Butantan Institute in São Paulo has completed the most extensive genetic sequencing to date of the golden lancehead viper (Bothrops insularis), focusing on its venom-related genes. The species, which shares most of its genes with the other 48 jararaca vipers, now serves as a reference for studying how these snakes and their toxins evolved. The work, published in Genome Biology and Evolution, offers new insight into both venom biology and conservation of this critically endangered snake.
The golden lancehead diverged from the mainland jararaca (Bothrops jararaca) after becoming isolated on Queimada Grande Island off the São Paulo coast about 100,000 years ago. Unlike the darker, ground‑dwelling mainland jararacas that primarily hunt small mammals, golden lanceheads have yellow skin, a semi‑arboreal lifestyle, and as adults feed on birds. Earlier research showed that their venom is more potent in birds than in mammals. According to lead author Pedro Nachtigall, "We didn't find major differences in the toxin genes, but it's likely that some protein or smaller piece of one of them may be enough to make the venom more lethal to birds."
Genome analysis revealed venom rich in enzymes and proteins that trigger bleeding and coagulation problems, as well as effects such as hypotension and tissue damage, similar to continental jararacas. The team also found that genetic changes in the species are shaped more by natural selection than by random genetic drift, despite the population being confined to a small island of 43 hectares. As senior author Inácio Junqueira de Azevedo notes, the specific pattern of variation indicates selective pressure, possibly linked to diet or geographic restriction.
The study sequenced the complete genome of a male golden lancehead and obtained less detailed genomes from eight additional snakes, seven wild and one from an ex situ conservation program. Comparing these genomes helps assess genetic variability and the genetic health of captive animals, informing conservation strategies. Transcriptome data from venom glands of four individuals, building on earlier work by Junqueira de Azevedo, further illuminated toxin gene evolution and the origin of a toxin subtype.
Using the high‑resolution genome, the researchers reconstructed demographic history over roughly 100,000 years. Modeling suggests an ancestral continental population of about 140,000 snakes, followed by isolation on the landmass that became Queimada Grande and two severe population declines associated with changes in sea level. A more gradual decline between 10,000 and 5,000 years ago led to a population size consistent with current estimates of 2,000–4,000 snakes. According to Junqueira de Azevedo, the resulting genomic resource provides a robust foundation for population, evolutionary, conservation, genomic, and venom studies, including potential applications such as anticoagulant and blood pressure‑lowering drugs.
The golden lancehead diverged from the mainland jararaca (Bothrops jararaca) after becoming isolated on Queimada Grande Island off the São Paulo coast about 100,000 years ago. Unlike the darker, ground‑dwelling mainland jararacas that primarily hunt small mammals, golden lanceheads have yellow skin, a semi‑arboreal lifestyle, and as adults feed on birds. Earlier research showed that their venom is more potent in birds than in mammals. According to lead author Pedro Nachtigall, "We didn't find major differences in the toxin genes, but it's likely that some protein or smaller piece of one of them may be enough to make the venom more lethal to birds."
Genome analysis revealed venom rich in enzymes and proteins that trigger bleeding and coagulation problems, as well as effects such as hypotension and tissue damage, similar to continental jararacas. The team also found that genetic changes in the species are shaped more by natural selection than by random genetic drift, despite the population being confined to a small island of 43 hectares. As senior author Inácio Junqueira de Azevedo notes, the specific pattern of variation indicates selective pressure, possibly linked to diet or geographic restriction.
The study sequenced the complete genome of a male golden lancehead and obtained less detailed genomes from eight additional snakes, seven wild and one from an ex situ conservation program. Comparing these genomes helps assess genetic variability and the genetic health of captive animals, informing conservation strategies. Transcriptome data from venom glands of four individuals, building on earlier work by Junqueira de Azevedo, further illuminated toxin gene evolution and the origin of a toxin subtype.
Using the high‑resolution genome, the researchers reconstructed demographic history over roughly 100,000 years. Modeling suggests an ancestral continental population of about 140,000 snakes, followed by isolation on the landmass that became Queimada Grande and two severe population declines associated with changes in sea level. A more gradual decline between 10,000 and 5,000 years ago led to a population size consistent with current estimates of 2,000–4,000 snakes. According to Junqueira de Azevedo, the resulting genomic resource provides a robust foundation for population, evolutionary, conservation, genomic, and venom studies, including potential applications such as anticoagulant and blood pressure‑lowering drugs.