My research is broadly centered around understanding the origin of shape diversity and the connection between form and function. To date I have focused on fishes, which have more species diversity that all other vertebrates combined. My approach relies on geometric morphometric methods to investigate patterns of morphological change and I frequently integrate shape data with genetic, environmental, or phylogenetic data to better understand broad evolutionary mechanisms.
Historical contingency, Pareto Optimality, and evolutionary constraints
One topic in evolutionary biology that I have consistently been drawn to, and frequently find myself enamored with, is how history influences adaptive peaks and evolutionary trajectories. Whether this is in the context of functional constraints imposed on a mechanical system, or developmental constraints imposed on patterning and phenotypic development, or evolutionary constraints that can marry the two, the field is rich with enticing
Most recently, I have utilized an enigmatic group of open water ocean fishes that are understudied owing to their ecology and life history, to explore how extreme phenotypes can introduce both functional and evolutionary constraints throughout a lineage. In this study, we found that extreme morphologies come not only with an anatomical trade-off, but also find evidence for evolutionary trade-offs. Further, we were able to link the contemporary anatomy of a group of fishes to a constraint that, we predict, has persisted in their ancestral state. For more details, please see Gilbert et al 2021. DOI: https://doi.org/10.1093/iob/obab003
Genotype to phenotype and the curiosities that surround plasticity
Phenotypic plasticity is a fascinating concept in biology that can be simplified as the capacity of a single genotype to produce a variety of phenotypes under different environments. Operationally, this capacity allows populations to adapt to rapidly changing environments. In spite of its ecological importance, several questions still exist, including how genetic systems can respond, or be rewired, in response to environmental cues. Using a number of approaches, my work aims to shed clarity on the genetic underpinnings of phenotypic plasticity how it is facilitated across different organisms. While some of my work has been centered around how the environment can shape morphology, other recent work has involved how both the environment and the genotype work in tandem to shape phenotype. For more information, please see Gilbert and Tetrault et al (2021, DOI: https://doi.org/10.1093/molbev/msab071) & stay tuned for Packard and Gilbert et al (in prep).
Contemporary evolution in response to anthropogenic change
The world is changing at ever increasing pace, largely due to human population growth and the demand for resources to sustain such growth. While anthropogenic change typically brings misfortune to ecological systems, some offer opportunities to study how rapid environmental change may spur evolution.
To this end, I’ve been exploring how rapidly changing environments can induce phenotypic responses in resident fish populations, on a timescale that can be measure in a few dozen generations. I have explored these concepts in a few different systems, including cichlids of the Tocantins River system in South America, which has been subjected to extreme damming and waterway manipulation over the past century. For more information, please see Gilbert et al 2020. DOI: https://doi.org/10.1111/eva.13080. Such rapid phenotypic shifts may arise due to the sorting of ancestral alleles, and/or phenotypic plasticity. Further work intends to assess the degree to which such anatomical changes may be driven by plasticity – stay tuned for Gilbert et al In prep where we shed light on the plasticity of specific craniofacial elements, including bone, muscle, and the interface between the two.