UNC Snake Expert Co-Authors Study about Evolution of Snake Venom

Stephen Mackessy

A team of researchers that includes University of Northern Colorado Biology Professor Stephen Mackessy has developed a new model for how venom in snakes evolved that could help scientists develop better anti-venoms and contribute to knowledge about gene evolution in humans and other animals.

Mackessy joined researchers at the University of Texas at Arlington and in the United Kingdom in analyzing groups of related genes in tissue from different parts of the Burmese python, which isn't considered venomous even though it has some of the same genes that have evolved into very toxic venom genes in other species.

Their findings were published in Molecular Biology and Evolution.

Researchers have found genetic evidence that highly toxic venom proteins were evolutionarily 'born' from non-toxic genes, which have other ordinary jobs around the body, such as regulation of cellular functions or digestion of food.

Mackessy continues to study and attempt to map the prairie rattlesnake genome, a DNA blueprint that's the equivalent of the human genome version for the snake, he said. He's especially interested in looking at where venom genes come from and how they have evolved.

"All animals share genetic similarity," said Mackessy, noting that even humans and bananas share 50 percent of genes. "But they don't look similar. So what is it that makes a human a human and a snake a snake? Humans, chimpanzees and gorillas are known to share most genetic information, but we certainly don't look alike. What are the small differences that determine a human trajectory rather than a great ape trajectory?"

When the mapping is finished, it will help set the stage for researchers to discover finer details; for example, why venom in some rear-fanged snakes is deadly to prey but not humans. The work also has potentially far-reaching implications in identifying differences in the same species that could help inform individualized medical treatment.

Mackessy uses a Star Trek analogy to help illustrate a point about future diagnosis. He said the films' handheld portable device used to instantly scan for medical conditions "doesn't sound so sci-fi" today with apps in development tied to strides in the genomic field, such as being able to pinpoint individual differences in DNA, providing a scientific framework for discovery and treating diseases.

Mackessy said other collaborations with University of Texas researchers include one whose lead author is UNC doctoral student Anthony Saviola. The study, which also involved a group from Valencia, Spain, was recently published in the Journal of Proteomics.

Another of his doctoral students, Cassandra Modahl, is lead author of a book chapter co-written with University of Texas professor Todd Castoe that details advances in genetic and protein technologies as applied to snake venoms.