VICTree
Variational inference for joint reconstruction of clonal trees and copy-number evolution from single-cell DNA sequencing data.
Python · variational inference · HMM
Research software

Italy · Portfolio
Machine Learning · Software Engineering · Maker / Geek

Selected work & open source
Research implementations, teaching material and software experiments.
Variational inference for joint reconstruction of clonal trees and copy-number evolution from single-cell DNA sequencing data.
Python · variational inference · HMM
Research software
Efficient sampling of random spanning arborescences, including directed graphs with low conductance where conventional walks struggle.
Python · random walks · dynamic programming
Open source
Single-cell phylogeny reconstruction with evolutionary distances derived directly from copy-number profiles.
Python · phylogenetics · copy numbers
Research software
A scalable rooted phylogenetic reconstruction method designed for single-cell copy-number data and its known diploid root.
Python · phylogenetics · neighbor joining
Research software
Open teaching material introducing modern R for statistical analysis, written for the Statistical Models MSc course at Politecnico di Torino.
R · statistics · Quarto
Open textbook
Peer-reviewed work & preprints
Probabilistic modelling and algorithms for computational biology.
bioRxiv preprint
Cellmates addresses single-cell tumour phylogeny reconstruction by deriving proper evolutionary distances from copy-number profiles and using those distances in phylogenetic reconstruction. The work was also presented at the 2026 Bertinoro Computational Biology Meeting.
@article{zampinetti2026cellmates,
author = {Zampinetti, Vittorio and Melin, Harald and Abdolhamdi, Marzie and Lagergren, Jens},
title = {Cellmates: a method for single-cell phylogeny reconstruction with proper evolutionary distances from copy numbers},
journal = {bioRxiv},
year = {2026}
}
bioRxiv · Cold Spring Harbor Laboratory
Rooted Neighbor Joining variants offer a principled way to use the known diploid root when reconstructing phylogenies from copy-number data. Sparse Rooted Neighbor Joining extends this advantage to datasets whose size places the full distance matrix out of reach, reducing running time with only a minor loss of accuracy in the evaluated settings.
@article{zampinetti2026srnj,
author = {Zampinetti, Vittorio and Melin, Harald and Hallin, Alva and Lagergren, Jens},
title = {Scalable and robust phylogenetic tree reconstruction from copy-number data with Sparse Rooted Neighbor Joining},
journal = {bioRxiv},
year = {2026},
doi = {10.64898/2026.07.30.739152}
}
Statistics & Probability Letters · Elsevier
Sampling random spanning arborescences in directed graphs is important for network analysis, optimisation and machine learning. Inspired by Wilson’s algorithm, this work uses dynamic programming to compute random-walk probabilities, avoiding inefficient walk simulations and unstable Laplacian determinant calculations. The approach improves efficiency and sampling quality, particularly on low-conductance graphs.
@article{treesampling2025,
author = {Zampinetti, Vittorio and Melin, Harald and Lagergren, Jens},
title = {Sampling random spanning arborescences in graphs with low conductance},
journal = {Statistics & Probability Letters},
volume = {226},
pages = {110481},
year = {2025},
doi = {10.1016/j.spl.2025.110481}
}
Research in Computational Molecular Biology (RECOMB) · Springer Nature Switzerland
Clonal tree inference brings crucial insights to the analysis of tumour heterogeneity and cancer evolution. VICTree is a variational-inference algorithm for joint Bayesian inference of clonal trees, built on a novel tree-structured mixture hidden Markov model. Experiments on simulated data and samples of multiple myeloma and breast cancer evaluate clustering, tree reconstruction, copy-number evolution and model selection.
@inproceedings{victree2024,
author = {Melin, Harald and Zampinetti, Vittorio and McPherson, Andrew and Lagergren, Jens},
title = {VICTree - A Variational Inference Method for Clonal Tree Reconstruction},
booktitle = {Research in Computational Molecular Biology},
pages = {429--433},
year = {2024},
publisher = {Springer Nature Switzerland}
}
Notes from research and beyond
Short updates on publications, conferences and technical work.
A short note on defending my PhD thesis and closing an important research chapter.
Presenting the final Cellmates results at the Bertinoro Computational Biology Meeting.
Our article on sampling random spanning arborescences is now available as open access.
Early Cellmates work and a week of computational biology talks in Bertinoro.
A presentation on variational inference for clonal tree reconstruction at SIS 2024.
Presenting our variational-inference work at RECOMB in Boston.