image: Somatic mutations acquired early in embryogenesis result in the profoundly polyclonal architecture of the mature cortex. Cells that acquire somatic mutations very early in development, for example, blastomeres in the morula (pink, green, blue, or purple) form clones of pluripotent cells, which then segregate into organs derived from all three germ layers (left panel). Within the cerebral cortex, these pre-gastrulation somatic mutations mark spatially adjacent but deeply clonally divergent neurons (right panel). Although clonal dispersion may be restricted tangentially (for example, pink neurons bounded by pink background, inset), closely related neurons are extensively intermingled with neurons that share no clonal connection closer than gastrulation. Cresyl violet stain of human primary somatosensory cortex in right panel is modified from S. Durinck, P. T. Spellman, E. Birney, W. Huber, Mapping identifiers for the integration of genomic datasets with the R/Bioconductor package biomaRt. Nat Protoc 4, 1184 (2009). This material relates to a paper that appeared in the Oct. 2 2015, issue of Science, published by AAAS. The paper, by M.A. Lodato at Howard Hughes Medical Institute in Boston, MA, and colleagues was titled, "Somatic mutation in single human neurons tracks developmental and transcriptional history." view more
Credit: Mollie B. Woodworth