Spatial variation in mutation rate within the plant shoot apical meristem

Here, we identified mutations that accumulated in clonally distinct meristem cell layers during several decades of vegetative propagation for two potato cultivars, Desiree and Urgenta. Mutations are the ultimate source of all genetic variation. Understanding biochemical processes that result in new mutations is often confounded by selection, and in multicellular plants, the stratification of cells into clonally distinct lineages. To identify and characterize a large number of new mutations with minimal exposure to selection, we carried out genome sequencing of Desiree and Urgenta tissue samples that were enriched for the different lineages. By comparing samples to appropriate outgroups and to each other, we identified and characterized mutations that accumulated in distinct cell lineages within each potato cultivar.