Emilie Richards

Under construction, so please bear with

Hybridization is a long recognized yet still mysterious process with a fascinating diversity of potential evolutionary outcomes. The genomic consequences of hybridization are particularly dynamic, and one outcome that I am particularly enamored with is that hybridization may contribute to the evolutionary potential of lineages to turn into adaptive radiations. Just think about how thrifty a little DIY upcycling can be!

About Me

I am an evolutionary biologist, currently a postdoctoral fellow working in Suzanne McGaughs lab at the University of Minnesota.

I never thought I could be a scientist growing up and I only expressed mild interest in the weird things animals did as a child. I got started on the path to science by being interested in becoming a real-world mermaid: I thought marine biology must involve a lot of scuba-diving, and have been stumbling my way towards a career in science ever since.

I enjoy making up 'would you rather' scenarios to pester friends with, scuba-diving, and annoying my cat Tonks. An utterly mundane yet slightly unhinged interest that I picked up during the pandemic is becoming friends with a murder of crows that visit my yard.

Research

Adaptive radiations are central to our understanding of evolution because they generate a wealth of ecological, phenotypic, and species diversity in rapid bursts. The availability of resources in new environments with few competitors has long been seen as the major force driving adaptive radiations, but it is a longstanding question why only some lineages rapidly diversify in response to such ecological opportunities while others do not. A growing number of studies have identified extensive hybridization and introgression across a range of adaptive radiations, contributing to the emerging view that gene flow may play a key role in adaptive radiation. However, it is still unclear how often hybridization is necessary for rapid diversification, as opposed to simply being pervasive throughout the history of any young rapidly diversifying group.

My strategy so far for examining the role hybridization has had on radiations has been a comparative population genetic and experimental hybridization approach. I work mainly with a microendemic radiation of Caribbean pupfish nested within many non-radiating pupfish lineages, but have also dabbled with radiations of cichlids in Cameroonian crater lakes.

CV

Publications

Highlights from my research. See my google scholar page for more publications.

Spatiotemporal landscape of adaptive radiation

The origins and processes underlying adaptive radiations are poorly understood. In this study, we explored evidence for two longstanding hypotheses of adaptive radiation: hybrid swarm origins and temporal stages of adaptation in Caribbean pupfish. Characterizing the spatiotemporal landscape of genetic variation across the Caribbean – we discovered that this microenemdic radiation is just the tip of the iceberg! This radiation represents the intersection between several pools of old standing variation from disjunct geographic sources that has been reassembled into new adaptive combinations.

The paradox of adaptive radiation

The hallmark rapid burst of speciation events during adaptive radiations presents quite the paradox to our understanding of speciation from theoretical models. In this review we explore how adaptive radiations stand in contradiction to predictions from speciation models like continuously decelerating diversification and propose some mechanisms that might help resolve the paradox.

Sympatric speciation meets secondary gene flow

Sympatric speciation means two different things to empirical and theoretical biologists. Recent genomic analyses of classic sympatric speciation examples have revealed complex histories of secondary gene flow from outgroups that challenge their sympatric status. As future fine-scale investigations of introgression will likely continue to paint a complex picture of the role of secondary gene flow in speciation, we explore how investigating the role that gene flow played in the process might help reconcile diverse theoretical models with existing empirical examples of sympatric speciation. I don’t pretend to have all the answers here, but it sure was fun to think about!

Systematic errors & gene tree heterogeneity

How much gene tree variation is biological? Using posterior prediction approaches to test model adequacy, we explored the relative importance of biological vs. methodological factors in explaining gene tree heterogeneity. Well quite a lot of variation in our mitochondrial gene trees was explained by poor model fit!

Student Research Posters

Seeing Yourself In Science DeCal

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