PHYFUM: Phylogenetic Reconstruction of Normal and Pre-malignant Tissue Evolution Using Fluctuating Methylation.

We present PHYFUM, a novel Bayesian phylogenetic method for methylation data that reconstructs the evolutionary history of stem cells and the glandular structures they reside within in normal tissue. Using simulations, we validated this phylogenetic method and confirmed its accuracy. A re-analysis of 22 patients unveiled early gland divergence in the human gut, in contrast to a much later common ancestor in the endometrium, and yielded strong evidence against gland division by segregation of individual stem cells.