Mutation distribution density in tumors reconstructs human’s lost diversity

Introductory ParagraphMutations do not accumulate uniformly across the genome. Human germline and tumor mutation density correlate poorly, and each is associated with different genomic features. Here, we analyze the genome-wide distribution of mutation densities in human and non-human Great Ape (NHGA) germlines as well as human tumors. Strikingly, non-human Great Ape germlines present higher correlation with tumors than the human germline does. This situation is mediated by a different distribution in the human germline of mutations at non-CpG sites, but not of CpG>T transitions. We propose that the impact of ancestral and historical human demographic events on human mutation density leads to this specific disruption in its expected genome-wide distribution. Tumors partially recover this distribution by the accumulation of pre-neoplastic-like somatic mutations. Our results highlight the potential utility of using Great Ape population data, rather than human controls, to establish the expected mutational background of healthy somatic cells.