prey vs predator relationship labs biology

“In the case of snake predators, this could lead to a more expansive venom toolkit, with a more diverse set of tools to subdue prey,” Schield said. The researchers hypothesized that balancing selection, rather than directional selection, maybe a better way to explain the ongoing arms race between snake predators and their prey. Balancing selection maintains genetic diversity and allows multiple functional versions of a gene to persist over time. “The issue with this hypothesis is that we know prey evolve the ability to resist venom, imposing reverse selection pressure back onto snake predators to evolve more diverse venom repertoires to circumvent prey resistance,” Schield said. “The ecological context of these predator-prey dynamics seemed to us to be quite inconsistent with strong directional evolution of venom since this would eventually leave snakes without sufficient genetic diversity to keep pace with prey resistance.” Researchers have long presumed that snake venom evolves in a directional fashion, with natural selection favoring a single “best” form of venom for killing prey.

Snake venom is comprised of a toxic mix of proteins and enzymes and is delivered through a bite which kills or immobilizes prey. Over time prey may evolve mechanisms to resist snake venom, and snakes in turn may evolve newvenom components to kill prey more effectively. The team’s findings overturn decades of thought on what factors shape venom gene evolution and venom variation, Castoe said. “We sequenced the genomes of rattlesnakes across the western United States to investigate genetic diversity in parts of the genome that encode venom components that enable the snakes to kill prey,” Schield said. “Ultimately, our focus was to test how deep or shallow the ‘gene pools’ of major venom components might be.” Todd Castoe, UTA professor of biology Lead author of the paper is Drew Schield, a postdoctoral fellow in Ecology and Evolutionary Biology at the University of Colorado at Boulder who received his Ph.D. in Quantitative Biology from UTA in 2018. “It turns out that the arms race between snakes and prey ends up favoring the constant re-shuffling of venom variants that are favored, leading to the retention of lots of venom variants over time, some of which are ancient.” “Our findings help explain decades of seemingly contradictory theory and evidence for what drives the extreme variation observed in snake venoms,” said Todd Castoe, UTA professor of biology and a co-author of the study. The team published its findings in a paper titled “The roles of balancing selection and recombination in the evolution of rattlesnake venom ,” which appears in the July 18 edition of the journal Nature Ecology and Evolution. New research by a team including biologists at The University of Texas at Arlington provides fresh insight on how rattlesnakes evolve to maintain an advantage in the ongoing “arms race” between snake venom and prey resistance.

Prey vs predator relationship labs biology