James DiFrisco awarded the 2023 BJPS Popper Prize

Crick Group Leader and philosopher of science, James DiFrisco, has been awarded the 2023 BJPS Popper Prize from the British Journal for the Philosophy of Science, for his article on the genetic basis of homology. 

James DiFrisco

The same but different? A theory of how the same body parts persist in different species, despite genetic divergence. 

Homology, the presence of the same body part in different species, has been a central organising idea in biology since pre-Darwinian times. Darwin and his peers introduced the evolutionary perspective that traits are shared across species due to shared ancestry, and more recent thinking is that homologies must be based on the same underlying developmental genes. However, the latter is not always the case: a classic example is sex difference, where the gene networks that related species use to establish biological maleness or femaleness can be wildly different, without changing the outcome. This phenomenon – different genotype, homologous phenotype– is known as Developmental System Drift (DSD), and it's thought to be widespread in nature.

Is there a useful way of thinking about all this? In this paper, James DiFrisco provides a detailed synthesis of the extensive literature on the subject, and proposes a unifying theory of homology that combines existing work in developmental and evolutionary genetics – areas of biology that are normally isolated from one another. The theory aims to explain why some genetic mechanisms for homologous traits are conserved while others are not.

Read the paper in the British Journal for the Philosophy of Science

The award is named after Karl Popper, who is regarded as one of the most influential philosophers of science in the twentieth century.

James joined the Crick in 2023 as the institute’s first philosopher of science. With a focus on the evolution of development, members of his team work on understanding how distinct body parts or ‘modules’ evolve, from gene networks to cell types to tissues.  

James’ winning paper grew out of a collaboration with biologist Günter Wagner at Yale University. The two have co-authored a series of four papers developing a genetic model of homology, or the same trait in different species. James argues that rather than seeing this model as competing with other models, it’s more helpful to consider them as complementary, feeding into a broader integrative theory. 

As the Crick’s only philosopher by training, James also hopes to create a culture in the community where science can fruitfully interact with theory and philosophical thinking. Examples of this include an upcoming theory workshop on the origin of novel cell types, as well as the institute’s new lecture series called ‘Being Human ’ which explores topics in philosophy of science of interest to scientists.  

James said: “A lot of biology is rightfully focussed in on the details, but some aspects of philosophy can help keep the bigger picture in view, and encourage innovative thinking at the boundaries of established knowledge.  The prospect of expanding on the kinds of ideas developed in my paper with a deeper cross-disciplinary approach is part of what drew me to the Crick.”

Paul Nurse, the Crick’s director said: “The Crick’s ethos is to make life-changing discoveries without boundaries, and we’re delighted to have a philosopher bringing fresh and different insight into our biological research. Congratulations to James for being awarded the important Popper Prize!”


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