Biology subjects

De La Fuente, C. A.

Publications and source records attributed to De La Fuente, C. A..

2 recordsLinked to original sources

bioRxiv2024

Cryptic host phenotypic heterogeneity drives diversification of bacteriophage {lambda}

Bacteriophages, the most abundant and genetically diverse life forms, seemingly defy fundamental ecological theory by exhibiting greater diversity than their numerous bacterial prey. This paradox raises questions about the mechanisms underlying parasite diversity. To investigate this, we took advantage of a surprising experimental result: when bacteriophage {lambda} is continually supplied a single host, {lambda} repeatedly evolves multiple genotypes within the same flask that vary in their receptor use. Measurements of negative frequency-dependent selection between receptor specialists revealed that diversifying selection drove their evolution and maintenance. However, the source of environmental heterogeneity necessary to generate this type of selection was unclear, as only a single isogenic host was provided and replenished every eight hours. Our experiments showed that selection for different specialist phages oscillated over the 8-hour incubation period, mirroring oscillations in gene expression of {lambda}s two receptors (Escherichia coli outer membrane proteins LamB and OmpF). These receptor expression changes were attributed to both cell-to-cell variation in receptor expression and rapid bacterial evolution, which we documented using phenotypic resistance assays and population genome sequencing. Our findings suggest that cryptic phenotypic variation in hosts, arising from non-genetic phenotypic heterogeneity and rapid evolution, may play a key role in driving viral diversity.

evolutionary biology↗

bioRxiv2023

Competition-driven eco-evolutionary feedback reshapes bacteriophage lambda's fitness landscape and enables speciation

A major challenge in evolutionary biology is explaining how populations navigate rugged fitness landscapes without getting trapped on local optima. One idea illustrated by adaptive dynamics theory is that as populations adapt, their newly enhanced capacities to exploit resources alter fitness payoffs and restructure the landscape in ways that promote speciation by opening new adaptive pathways. While there have been indirect tests of this theory, none have measured how fitness landscapes deform during adaptation, or test whether these shifts promote diversification. Here, we achieve this by studying bacteriophage , a virus that readily speciates into co-existing receptor specialists under controlled laboratory conditions. We used a high-throughput gene editing-phenotyping technology to measure s fitness landscape in the presence of different evolved- competitors and found that the fitness effects of individual mutations, and their epistatic interactions, depend on the competitor. Using these empirical data, we simulated s evolution on an un-changing landscape and one that recapitulates how the landscape deforms during evolution. heterogeneity only evolved in the shifting landscape regime. This study provides a test of adaptive dynamics, and, more broadly, shows how fitness landscapes dynamically change during adaptation, potentiating phenomena like speciation by opening new adaptive pathways.

evolutionary biology↗