Numbers of Mutations within Multicellular Bodies: Why It Matters

Multicellular organisms often start life as a single cell. Subsequent cell division builds the body. Each mutational event during those developmental cell divisions carries forward to all descendant cells. The overall number of mutant cells in the body follows the Luria-Delbruck process. This article first reviews the basic quantitative principles by which one can understand the likely number of mutant cells and the variation in mutational burden between individuals. A recent Frechet distribution approximation simplifies calculation of likelihoods and intuitive understanding of process. The second part of the article highlights consequences of somatic mutational mosaicism for understanding diseases such as cancer, neurodegeneration, and atherosclerosis.

Automated summary

Multicellular organisms start as a single cell and develop through cell division. Mutations occurring during development are inherited by all descendant cells, leading to a variable number of mutant cells in the body. This article discusses the quantitative principles of estimating the number of mutant cells and the variability between individuals using a Frechet distribution approximation. It also examines the implications of somatic mutational mosaicism for understanding diseases like cancer, neurodegeneration, and atherosclerosis.