Marjory Stephenson Prize Lecture: Professor Julian Parkhill

Posted on June 1, 2021   by Laura Cox

The Marjory Stephenson Prize is awarded annually to an individual who has made exceptional contributions to the discipline of microbiology. The 2020 Marjory Stephenson Prize was awarded to Professor Julian Parkhill. Professor Parkhill gave the lecture titled ‘Twenty years of sequence-gazing’ at the Microbiology Society's Annual Conference Online 2021.

Professor Julian Parkhill began his lecture by reflecting on his time as a member of the Microbiology Society, having joined as a PhD student. His talk, which he described as a ‘greatest hits compilation’ detailed a number of projects he and colleagues have carried out over 20 years.  

Professor Parkhill discussed the modern scientific cycle, in which a hypothesis is established and tweaked based on findings. However, he noted, in most cases a hypothesis is needed before funding is granted. But how can a hypothesis be established without data? Professor Charles Darwin spent six years exploring data before formulating a hypothesis, then a further 22 years proving this hypothesis, publishing the Origin of Species in 1859.   

Professor Parkhill’s research is mainly in bacterial genomes, the complete DNA sequence of an organism. He noted that the function of the majority of bacterial genes is unknown, using the genome of Neisseria meningitidis as an example. Genomes are a great way to see how an organism has evolved, he said, highlighting that evolution is ‘a tinkerer’ and works by modifying what already exists, not by creating perfect solutions. 

Professor Parkhill explained how he and colleagues used the genome of Salmonella Typhi to understand which genes allow the bacterium to infect different hosts. They found that the evolution of Salmonella Typhi works in the opposite way than they expected; the bacterium becomes more specialised to certain hosts as a result of gene loss, restricting the bacteria to a single host.  

By looking at genome sequences of multiple isolates and strains of a species of bacteria, Professor Parkhill and colleagues were able to notice patterns, which they could then use to generate a hypothesis. They used this technique to explore the evolution of a number of bacteria, including Staphylococcus aureus, Escherichia coli and Salmonella and used the genomes of S. aureus to track evolution of antimicrobial resistance around the world. Approaching the data with an open mind is essential, he said, to make new discoveries.  

Professor Parkhill ended his Lecture by thanking his previous collaborators and funding bodies who have supported the research. Finalising by highlighting the importance that international collaboration has had on his research, having had over 3,500 co-authors on his scientific publications. The session was completed by a Q&A session with Professor Sharon Peacock and Professor Gordon Dougan, who nominated Professor Parkhill for the prize.   

To learn more about Professor Julian Parkhill's research read our recent Q&A.

You can view Professor Parkhill’s full Prize Lecture below.