What is the genetic basis of adaptation to highly variable ecosystems?


Species living in rapidly fluctuating environments often harbor genetic variation that is both beneficial and deleterious on a habitat dependent basis. In this context, species can rapidly evolve to track the shifting fitness landscape (i.e., adaptive tracking) and maintain adaptive genetic variation. While theoretical work has explored the expected evolutionary dynamics of adaptive tracking, we still have an incomplete understanding of how prevalent adaptive tracking is in the wild or the functional loci that are targeted by this process. To tackle this knowledge gap, my work combines tools from population genomics, ecology, and computational biology.

Evolutionary genomics of rapid adaptation in worldwide fly populations:

Characterizing adaptive tracking in seasonal environments

Rapid evolution is ubiquitous in nature and allows adaptation to occur in few generations. Yet, we still lack a rigorous understanding of the circumstances and mechanisms governing this process. Fruit flies (Drosophila melanogaster) living in temperate regions experience strong fluctuations in the strength and direction of selection due to seasonality and evolve rapidly to track the changing fitness landscape. Consequentially, seasonally adaptive tracking represents a natural laboratory in which to understand whether rapid evolution is a repeatable and predictable process. In my current project I use the largest genomic datasets for natural propulations of Drosophila, DEST (https://dest.bio),  to investigate the patterns of adaptive variation and demography  in natural of D. melanogaster flies exposed to seasonally varying selection. This work seeks ot provide insights to about the consequences of rapid evolution in natural populations as a result of anthropogenic climate change, agricultural practices. Moreover, the issue of rapid adaptation taps into a fundamental corollary in evolutionary biology: the idea that evolution is a slow process governed by random genetic drift, where adaptive events are rare outliers. Accordingly, my research will provide insights of whether rapid evolution undermines or synergizes with the current zeitgeist of population genetics.

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The core samples of the DEST database reveal worldwide structure

My talk about overwintering demography in drosophila given at the 2021 DrosEU meeting

Ecological and evolutionary genomics of the northern acorn barnacle across ocean basins:

Characterizing adaptive tracking in intertidal environments

My work leverages  the biology of the northern acorn barnacle (Semibalanus balanoides) to as two questions: first, how functional genetic variation is maintained in highly heterogeneous environments. And, second, whether adaptations to environmental heterogeneity is fueled by young alleles that constantly enter the population but fail to establish in the long term, or rather, by old alleles that are maintained over long evolutionary timescales.

This project in the media

Barnacles offer genetic clues on how organisms adapt to changing environments

By Phoebe Hall, Assistant Director of BioMedical Communications, Division of Biology and Medicine


An NSF highlights video about my barnacle work (2020)

2019 Evolution Meeting talk about intertidal dynamics of the Mpi gene in barnacles

Brown EEOB departmental seminar (2019)