Leon Hafner

Leon Hafner

Machine Learning for Biology
Previously @ Arc Institute

Munich, Germany

About Me

I work at the interface of machine learning and computational biology, with a focus on perturbation modeling, single-cell genomics, and generative models. Most recently, I was an ML research intern in the Machine Learning Group at Arc Institute, supervised by Yusuf Roohani and Hani Goodarzi. My work focused on understanding how current perturbation models, which have largely been developed on comparatively simple cell-line perturbation datasets, perform on highly heterogeneous in vivo data spanning many diverse and continuous cell types and cell states.

Before Arc, I completed my Master's thesis in Fabian Theis's lab at Helmholtz Munich. I developed a conditional flow-matching model to predict cellular responses to transcription-factor perturbations and identified previously unknown TF combinations for reprogramming fibroblasts into dendritic cells.

I am convinced that the strongest ML systems for biology come from understanding the biological context deeply and tailoring the modeling approach to it, using prior knowledge and structure in the biological data rather than treating the problem as a generic ML task.

Research Experience

Mar 2026 - Jul 2026

ML Research Intern

Machine Learning Group, Arc Institute

Evaluated perturbation models on large-scale in vivo single-cell CRISPR screens, focusing on generalization across heterogeneous cell types and cell states.

Aug 2025 - Jan 2026

Master's Thesis

Theis Lab, Helmholtz Munich

“Generative Modeling of Cellular Reprogramming with Flow Matching.” Developed a conditional flow-matching model to predict cellular responses to transcription-factor perturbations and identify previously unknown TF combinations for reprogramming fibroblasts into dendritic cells.

Publications

Single-cell differential expression analysis between conditions within nested settings.
Leon Hafner, Gregor Sturm, Sarah Lumpp, Mathias Drton, Markus List.
Briefings in Bioinformatics (2025), doi.org/10.1093/bib/bbaf397
Network medicine-based epistasis detection in complex diseases: ready for quantum computing.
Markus Hoffmann, [...], Leon Hafner, [...], Markus List, David B. Blumenthal.
Nucleic Acids Research (2024), doi.org/10.1093/nar/gkae697

Education

2023 - 2026

MSc Bioinformatics

Technical University of Munich
2019 - 2023

BSc Bioinformatics

Technical University of Munich

Technical Expertise

ML & Modeling

PyTorch Generative Modeling Flow Matching Perturbation Modeling

Single-Cell & Genomics

scRNA-seq CRISPR Screens Scanpy / AnnData Differential Expression