The R.A. Fisher Prize

About the R. A. Fisher Prize

R. A. Fisher Prize

The R. A. Fisher Prize is awarded annually by the Society for the Study of Evolution for an outstanding Ph.D. dissertation paper published in an issue of the journal Evolution during a given calendar year. Applications open in the fall and close January 31.

This prize pays tribute to one of the most distinguished evolutionists of the 20th Century, Sir Ronald Fisher, who with JBS Haldane and Sewall Wright, developed theoretical population genetics and established its central position within evolutionary biology.  Fisher’s interests ranged widely, but placed particular emphasis on the dynamics of mutation and selection and how these contribute to adaptation.


2019 Fisher Prize Winner: Dr. Matthew Zuellig

The 2019 Fisher Prize is awarded to Dr. Matthew Zuellig for his paper, “A two‐locus hybrid incompatibility is widespread, polymorphic, and active in natural populations of Mimulus” Evolution (2018) 72: 2394-2405. 

How do barriers that bar reproduction between two species arise and persist within each of the species, in spite of ongoing gene flow between them? To address this question, Dr. Zuellig studied two naturally hybridizing species of monekyflower, Mimulus guttatus and M. nasutus. He had previously identified a two‐locus hybrid lethality system, in which each species carries a hybrid lethality allele at a different locus, resulting in hybrid offspring that lack chlorophyll in F2 and later generations. Building on this finding, he here conducted extensive series of crosses with plants sampled across a large geographic range of western U.S. to map the spatial distribution of alleles underlying this system and estimate their frequencies. Because both species also have alternative alleles at substantial frequencies in some populations, hybrids do not necessarily result in lethality, allowing some introgression. This work elegantly explores how "speciation loci" that were first identified in the lab behave in real populations across their range. Dr. Zuellig earned his Ph.D. at the University of Georgia and is now a postdoctoral fellow at the University of Bern.

 Past Fisher Prize Winners

2018 Valerie Morley (more info)
2017 Megan Greischar (more info)
2016 Jennifer Lohr (more info)
2015 Alison E. Wright (more info)
2014 Amy Hurford (more info)
2013 William Soto
2012 David McCandlish
2011 D. Luke Mahler
2010 Britt Koskella
2009 Megan Higgie
2008 R. Brian Langerhans
2007 Guillaume Martin
2006 Maurine Neiman



The 2018 Fisher Prize was awarded to Dr. Valerie Morley for her paper, “Dynamics of molecular evolution in RNA virus populations depend on sudden versus gradual environmental change” Evolution (2017) 71:872-883.

Do organisms evolve differently in slowly versus rapidly changing environments? In this study, Dr. Morley examined the evolutionary dynamics of the RNA sequence of Sindbis virus, exposed either directly to a novel host or to a gradually increasing proportion of that host. By sampling and sequencing in depth at eight time points, Dr. Morley and co-authors were able to track the genetic changes that occurred in precise detail. Their study revealed that large-step mutations were more likely to fix during the early stages of evolution with a sudden host switch, but this pattern disappeared with a gradual switch. As selection was weaker and fixation took longer in the gradually changing treatment, there was more evidence of clonal interference and the fixation of clusters of mutations. By contrast, single mutations were more likely to sweep in the sudden treatment. By combining experimental evolution with whole-genome sequencing, the paper by Morley et al. provides novel insights into the ways that populations adapt to a changing world.



 The 2017 Fisher Prize was awarded to Dr. Megan Greischar, for her paper “Predicting optimal transmission investment in malaria parasites.” Evolution (2016) 70:1542-1558.

In this study, Dr. Greischar examined the growth-reproduction tradeoff faced by malaria parasites, which must allocate resources to within-host proliferation as well as the production of specialized life stages for onward transmission. The way parasites balance this tradeoff influences exploitation of host resources---and hence virulence---and the rate of disease spread through host populations. She built a within-host model to examine the conflicting selection pressures and identify the optimal allocation to transmission. She developed novel computational methods to consider a wide range of potential strategies, using splines to describe plastic allocation with few parameters. The model suggested that parasites benefit from delaying transmission stage production, just as macroorganisms can benefit from delayed reproductive effort. Innate immunity and coinfecting parasites imposed strong selection favoring parasites that invest disproportionately in proliferation rather than transmission (“reproductive restraint''), resulting in more rapid and extreme exploitation of host resources. Selection on transmission investment therefore represents one mechanism by which enhanced virulence could be adaptive for parasites. More generally, the approach can accommodate highly complex strategies within richly detailed ecological models, providing a much-needed alternative to analytical methods that could be adapted to diverse organisms.




The 2016 Fisher Prize was awarded to Dr. Jennifer N. Lohr, for her paper: Lohr, J. N., and C. R. Haag. 2015. Genetic load, inbreeding depression, and hybrid vigor covary with population size: An empirical evaluation of theoretical predictions. Evolution 69:3109-3122.

In this paper, Lohr and Haag test predictions from population genetic theory on the genetic consequences of small population size, a fundamental question in evolutionary biology. Lohr used eight natural populations of Daphnia magna that varied in effective population size, along with carefully designed crosses within and among populations, to test these predictions. She showed that Ne accurately predicted inbreeding depression, genetic load, and hybrid vigor, strongly supporting theoretical predictions based on recurrent mutation to unconditionally deleterious alleles. These results have important implications for evolutionary processes in natural populations, including for the evolution of dispersal, breeding systems, local adaptation, and aging.

Dr. Lohr received her PhD in 2015 from the Department of Biology at the University of Fribourg, with Christopher Haag. She is now a Postdoctoral Research Associate at the University of Hamburg with Susanne Dobler.



The 2015 Fisher Prize was awarded to Dr. Alison E. Wright, for her paper: Alison E. Wright, Peter W. Harrison, Stephen H. Montgomery, Marie A. Pointer and Judith E. Mank. 2014. Independent stratum formation on the avian sex chromosomes reveals inter-chromosomal gene conversion and predominance of purifying selection on the W chromosome. Evolution. 68(11):3281–3295.

In this paper, Wright and co-authors used a comparative approach across a monophyletic clade of birds, spanning 90 million years, to study the mode, mechanism and rate of divergence between the avian Z and W sex chromosomes. This work, based on the largest cross-species dataset of Z-W orthologs to date, revealed the complex recombinational history of the avian sex chromosomes. The results show that although birds share the same sex chromosome system, recombination between the sex chromosomes has been suppressed independently multiple times, allowing for convergent patterns of divergence. Wright and her co-authors also found that recombination and gene conversion persist on sex chromosomes over both long and short evolutionary trajectories. Importantly, the study shows that the female-limited and degenerated W chromosome is evolving with a significant contribution of purifying selection, indicating that the remaining W-linked genes play an important role in female-specific fitness.

Dr Wright received her PhD in 2014 from the Department of Zoology at the University of Oxford, with Judith Mank. She is now a Postdoctoral Research Associate at University College London.




The 2014 Fisher Prize was awarded to Dr. Amy Hurford for her paper: Hurford, A. and T. Day. 2013. Immune evasion and the evolution of molecular mimicry in parasites. Evolution 67(10): 2889-2904. Amy Hurford

Hurford explored a variety of hypotheses about the coevolution of vertebrate immune systems and pathogens, using mathematical models. One of her primary goals was to understand the evolutionary origins of infection-induced autoimmune disorders. She developed mathematical models using techniques from dynamical systems and game theory to better understand the conditions under which we might expect pathogens to evolve molecular mimicry. She and her coauthor analyzed the patterns of molecular mimicry that are expected under two hypotheses regarding molecular mimicry by parasites. One of their findings was that the highest risk of autoimmunity comes from parasites that display intermediate levels of mimicry. Interestingly, and highly relevantly, they also explored the consequences of different medical interventions on the evolution of mimicry and the incidence of autoimmunity.

Dr. Hurford received her Ph.D. in 2011 from the Department of Mathematics and Statistics at Queens University, where he was advised by Dr. Troy Day. Following postdoctoral appointments at York University and the University of Toronto, she began a faculty position at Memorial University of Newfoundland.


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