Jordan A. Lewis

Adaptive Evolution & Ecological Change

The Evolution of Host Defense in C. elegans

Parasites are ubiquitous and invoke high fitness costs on hosts. As such, host populations tend to evolve elevated defenses against their parasites. However, the characteristics of the defenses hosts develop may depend on the dynamics of their interactions with their parasites over space and time. I use experimental evolution with pathogenic bacteria and the host nematode Caenorhabditis elegans to investigate questions related to the evolution of host defense.

Lewis JA, Kandala P, Penley MJ, Morran LT. (2023). Gene flow accelerates adaptation to a parasite, Evolution, 77 (6), 1468–1478. https://doi.org/10.1093/evolut/qpad048

Lewis JA, Penley MJ, Ahumada SD, Sylla H^Α, Morran LT. (2022). Antagonistic coevolution limits the range of host defense in C. elegans populations. Frontiers in Cellular and Infection Microbiology, 12. https://doi.org/10.3389/fcimb.2022.758745

Lab Evolution for Applied Science

Over the past few decades, laboratory study of evolution has become more commonplace and has assisted biologists in the basic sciences in illuminating mechanisms underlying fundamental processes. Artificial Selection, Directed Evolution, and Laboratory Natural Selection have all been used differently. However, one significant difference exists between the three methods: Lab Natural Selection remains comparatively underused in the applied biological sciences. In this review, we cover the history of evolution experiments in the lab, place lab natural selection in context with other experimental evolution methodologies, discuss the benefits of lab natural selection, and identify three areas where it could be used to help develop industrial and medical products.

Lewis JA & Morran LT. (2021). Advantages of laboratory natural selection in the applied sciences. Journal of Evolutionary Biology, 35, 5– 22. https://doi.org/10.1111/jeb.13964

Bacteria in Recreational Waters

Every year, thousands of people get sick following visits to recreational waters. Beaches, lakes, streams, and rivers are dynamic ecosystems that can house a variety of pathogenic microorganisms, so management agencies monitor these to determine overall water quality and pathogen risk. However, quantifying pathogen risk at any given time in these environments is challenging. Thus, fecal indicator bacteria are often used as a proxy to determine the general quality of the water. I am interested in the natural microbial communities present in these environments as well as the process of microbial monitoring and risk assessment.

Lewis JA, Frost VJ, Heard MJ. (Accepted). The Presence and Abundance of Escherichia coli in beach sediment following a Coastal Renourishment Project. PLOS ONE.

Lewis JA, Decker MB, Turner C, Kane E, Turner PE. (In Prep). Climate Change, Extreme Rain Events, and Fecal Indicator Bacteria: A Case Study on the Connecticut Coast. Marine Pollution Bulletin.

Phage Biology & Evolution

Bacteriophages are bacteria-specific viruses that naturally exist and are amongst the most numerous biological entities on the planet. As pure obligate parasites with specific host ranges, viruses and their bacterial hosts readily evolve in the laboratory, giving them immense usefulness in studying the evolution of parasite virulence and host resistance. Further, their ability to kill bacteria has led to their use in medicine through Phage Therapy. I am interested in phage therapy in humans, veterinary medicine, and food preparation, as well as using general phage biology to understand host-parasite interactions and adaptive evolution.

Stay tuned for phage work from my postdoc! An NSF Postdoctoral Fellowship in Biology funds this work. Find more details about the grant here.

Lewis JA, Turner PE, Chan BK, Vong G. (Proposal Accepted for 2024 volume). Advancing Health and Healthcare Equity through Phage Therapy. Annual Review of Virology.

Adaptive Evolution and Trade-Offs

As populations move through their environment over space and time, they will be forced to adapt to biotic and abiotic stressors. I am interested in factors that serve to facilitate or impede adaptation. Further, I am interested degree to which the results of the forces of evolution can be predicted within these situations.

Within these contexts, organisms can face external stimuli that select for conflicting, or mutually exclusive adaptation. Here, populations face a “trade-off” where evolution in response to one stimulus causes an increase in fitness in one trait, but that trait comes at the expense of another (potentially significant) trait. Some of my ongoing projects look at tradeoffs faced by opportunistic pathogens as they adapt to the environment and how adaptation to one parasite influences the ability to adapt to others.

Lewis JA, Blazanin M, Kane E, An W, Turner P. (2023). The Enemy of My Enemy: Exploring Tradeoffs between Virulence and Host Defense in an Opportunistic Bacterial Pathogen. TBD