See Supplementary Table 1 for sample identities. The primary tumor is labeled “PDAC” while the PanINs are labeled by letters. Gene names in orange text are SNVs/INDELs, in blue are copy-number losses, and in red are copy-number gains affecting putative driver genes. The sequencing data for each driver gene variant was manually reviewed to verify phylogenetic position. For each phylogeny, the numbers of acquired mutations are in black font. The branch lengths are proportional to the number of SNVs/INDELs. The dashed lines indicate branches that have been extended to accommodate gene annotation and variant numbers. For each Bayesian heat map, samples are indicated on each row while variants are represented by each column. The color of each tile indicates the probability that the variant is present or absent in the corresponding sample. Dark blue indicates a variant with a >99.9% probability of being present, while dark red indicates a variant with a >99.9% probability of being absent. Light blue and red tiles indicate lower probabilities, and white tiles indicate approximately a 50% probability. a. PIN106. The node leading from the first MRCA to the second MRCA has a confidence value of >99% and the node leading from the second MRCA to the third MRCA has a confidence value of 82%. b. PIN107.