Genome embedded ribonucleotides: causes and consequences (360G-Wellcome-204802_Z_16_Z)

Knowledge of the mechanisms of mutagenesis is essential in understanding how genetic variation is generated, to be distributed through populations by migration, selection or drift. Mutations are non-randomly distributed throughout the genome, occuring despite the exquisite fidelity of DNA replicative processes. Ribonucleotides are the most common non-canonical nucleotides. They may arise from sporadic misincorporation of ribonucleotides by DNA polymerases during replication, or from the retention of RNA primers. As embedded ribonucleotides are known to be mutagenic, we hypothesise that their retention leads to a distinctive mutational signature(s) at such sites, contributing to the mutational landscape in yeast and humans. The goals of this proposal are to: 1. Define the genomic locations of embedded ribonucleotides. 2\. Establish whether embedded ribonucleotides at specific sites are single ribonucleotides misincorporated by polymerases, or retained primer tracts. 3\. Identify the mutational signature(s) associated with embedded ribonucleotides in yeast. 4\. Confirm that ribonucleotide-associated mutational signatures are present in mammalian genomes. Delineating the location, extent and consequences of embedded ribonucleotides will facilitate the interpretation of genetic variation in evolution and human genetic disease; identify and explain mutational processes associated with the development of cancer; and inform our understanding of Aicardi-Goutières syndrome, which arises from excessive ribonucleotide retention.