About us
We are the Pathogen Informatics and Modelling group at EMBL-EBI (also known as the Lees Group). On this page you can find information about current and past group members, who we work with, and some nice pictures.
Lab members
Hsueh-Chien (Raymond) Cheng is a visiting PhD student (based at the Wellcome Sanger Institute)

I am a PhD student at the Wellcome Sanger Institute in Prof. Stephen Bentley’s group and also under the supervision of Dr. John Lees at the EBI. My current work is focusing on quantifying the invasiveness of Streptococcus pneumoniae with different genetic backgrounds by using the WGS data among populations. I am also interested in studying various modes of evolution in pathogenic bacteria and how they shape different population structures.
Languages: Python, R
raymond at ebi dot ac dot uk
Berk Gonenc is a Master’s student

My background includes wet-lab as well as bioinformatics. I have a BSc in Molecular Biology and Genetics from the respected Bogazici University and worked in a NGS analysis bioinformatics company (Genomize) for nearly 2 years. I am now doing my MSc in “Biosciences and Bioengineering Innovations for Precision Medicine (BeInPM)” at the University Grenoble Alpes.
My internship will focus on developing a bayesian model of bacterial populations. I’m motivated to expand my knowledge on statistics and data analysis under Dr. John Lees supervision at EMBL-EBI.
Languages and tools: R, Python, Bash
berk at ebi dot ac dot uk
Joel Hellewell is an EIPOD fellow

My background is in transmission modelling and statistics. I did my PhD at Imperial College London in the Malaria group with Tom Churcher and Azra Ghani. I then did a post-doc at the London School of Hygiene and Tropical Medicine in Sebastian Funk’s group. I contributed towards models that performed routine short-term forecasts of COVID-19 deaths, hospitalisations, and reported cases in the United Kingdom. I also worked on reproduction number estimates and modelling the sensitivity of PCR tests over the course of a COVID-19 infection.
I am now interested in integrating genetic and epidemiological models and data to see if this improves the answers to key questions that were repeatedly asking during the COVID-19 pandemic. For example, how early can we tell that the number of infections is increasing? Does this novel variant have a transmission advantage? Does this novel variant cause infections with more serious outcomes?
Languages and tools: R, stan
joel at ebi dot ac dot uk
Samuel Horsfield is a visiting PhD student (based at Imperial College London)

My PhD focuses on pangenome evolution in pathogenic bacteria. I have designed and developed ggcaller, a new annotation tool for bacterial pangenomes that works on genome graphs. Other projects include using graph methods to improve adaptive sequencing of the accessory genome, and using large population datasets to compare rates of core and accessory genome evolution.
Languages and tools: C++, python
Organisms: Bacteria (S. pneumoniae, E. coli and many more) and viruses (polio).
shorsfield at ebi dot ac dot uk
John Lees is a research group leader

My previous work has attempted to understand the pathogenesis and transmission of infectious diseases. I primarily works on statistical genetics, genomic epidemiology and genome evolution of pathogenic bacteria. I have also worked on infectious disease modelling, GPU algorithms, and visualisation. I write methods and software to scale these analyses and make them more accessible to others in attempts to democratise bioinformatics.
Languages and tools: C++, CUDA, python, R, rust, stan
Organisms: Any microbe, but especially Streptococcal bacteria.
My personal website is www.johnlees.me and you can find my papers here.
jlees at ebi dot ac dot uk
Leonie Lorenz is a PhD student

In my PhD, I will focus on jointly using epidemiological and genomic data for developing mathematical models of pathogen transmission. While the spreading and evolution of pathogens are often analysed separately, exploiting both data streams together as input for epidemiological models could increase the models’ predictive power and result in new insights.
I studied biomathematics at the University of Greifswald, Germany. For my master thesis, I developed a Boolean model for the regulation of apoptosis at the Max Delbrück Center for Molecular Medicine in the Helmholtz Association.
Languages and tools: python, R
llorenz at ebi dot ac dot uk
Tommi Mäklin is a visiting postdoc

Tommi is currently visiting from Jukka Corander’s group at the University of Helsinki.
He has previously developed the tools mSWEEP
and mGEMS
for strain deconvolution
and genomic epidemiology from metagenomic sequencing data. While here, he will be working
on a Theory@EMBL project
to combine modelling with metagenomics methods and investigate competition dynamics between
strains during carriage and infection.
Languages and tools: C++, R, Stan, bash
Organisms: Gut microbes, E. coli.
tommi at ebi dot ac dot uk
Jacqueline Toussaint is a PhD student

While my PhD projects are still in the early stages, I’m broadly focused on creating bioinformatic tools for performing computational, statistical and biological analysis of bacterial genomic surveillance data. In particular, I’m interested in creating more efficient and accurate methods for performing genome-wide association studies (GWAS) in bacteria, with the possibility of expanding to browser-based real-time analysis.
I’ve previously studied Biochemistry and Microbiology at Montana State University, with my Bachelor’s thesis research focused on generating and analyzing multi-omics datasets. I’m excited to further my education in the lab of Dr. John Lees at EMBL-EBI and the University of Cambridge, UK.
Languages and tools: R, python
lilyjacqueline at ebi dot ac dot uk
Alumni
Gherard Batisti Biffignandi was a visiting PhD student (based at the University of Pavia).
Bruhad Dave was an intern.
Johanna von Wachsmann was a Master’s student (based at Freie Universität Berlin), now with Rob Finn.
Social and photos
2022

Infection Biology Transversal Theme Retreat

Group retreat at London Zoo (Gorilla sadly not in our group)
