In deciphering a simple but particularly deadly toxin, the research opens ways to explore how genes produce the trait
Credit: Michael B. Hogan, Florida State University
Tiger Rattlesnake has the simplest and most toxic venom of any type of rattlesnake, and now new research from a team led by a biologist at the University of South Florida can explain the genes behind the feared predator’s sting.
Published in the new issue ofProceedings of the National Academy of Sciences, “ Across the southeastern United States, Associate Professor in the Department of Integrative Biology at the University of South Florida Mark Margers and colleagues sequenced the genome of the tiger rattlesnake to understand the genotype of the toxin trait. Despite the simplicity of the venom of the Tiger Rattlesnake snake, Margres says it’s about 40 times more toxic than the venom of the Eastern Diamondback Rattlesnakes viper here in Florida.
Their work is the most complete characterization of the venom gene regulation network to date, and their identification of the key mechanisms in the production of a particularly toxic toxin will help scientists explain a wide range of genetic questions.
“Simple genotypes can produce complex traits,” Margers said. “Here, we showed that the opposite is also true – a complex genotype can produce simple traits.”
Margers collaborated with colleagues at Clemson University, Florida State University, and University of Southern Alabama on the project, which sought to explain whether differences in traits were derived from differences in the number of genes, their sequence, or how they were organized. Their work is only the second time the rattlesnake genome has been deciphered.
The genetic makeup of an organism is the set of genes it carries, and its phenotype is all its observable characteristics, which can be affected by its genes, the environment in which it lives, and other factors. Evolutionary biologists are working to understand how genes affect the variation in phenotype between similar organisms. In this case, they looked at why the different types of rattlesnakes differ in their toxin composition and toxicity.
The Tiger Rattlesnakes snake is native to the Sonoran Desert in southern Arizona and northern Mexico where the relatively small pit viper feeds on lizards and rodents. While some types of rattlesnakes have complex toxins generated by dozens of genes, Margres said the Tiger Rattlesnake venom is very simple – as many as 15 out of 51 toxin-producing genes are actively producing proteins and peptides that their prey attack the nervous system, forcing pressure Blood on the drop and causes blood clotting to stop.
The team found that the number of venom genes greatly outnumbered proteins produced in the simple phenotype, indicating that there is a complex process at the heart of the toxin and that Tiger Rattlesnakes have toxic genes to spare.
“Only about half of the toxin genes were expressed in the genetic makeup,” Margers said. “For me, the interesting part is why the unexpressed genes are still there? These genes can make functional toxins, but they don’t. This needs to be explored further.”
Besides understanding this single type of venomous snake, Margers said the research will aid the advancement of genetic science by showing the most common techniques in genetic research on mice and fruit flies, and the organisms that are often used in genetic studies, could also work when applied to Less. – The studied organisms such as snakes. The team used genetic sequencing techniques common in human genetics research, thereby opening the door for scientists to understand the relationship between genotype and phenotype in many other organisms.
Another potential side benefit of the research, Margres said, is that snake venom is used in medicine for humans to combat stroke and high blood pressure. The more scientists understand the poison, the better medical engineering can apply that knowledge in drug discovery and development.
The research was funded by the National Science Foundation and Clemson University.