Biology: A single-cell map of the human body

A description of the cell-type composition of all major human organs is presented in Nature. The RNA of over 500,000 single cells from Chinese Han donors was sequenced. These data will contribute to the international effort to complete a human cell atlas.

Cells in the human body all carry the same basic genetic information, but vary widely in the genes they express. The genes expressed in a given cell define its functions. Maps of single-cell gene expression across the body could help us to understand the functions of these cells and the factors that influence their activity. Such atlases have been created for some animals and individual human tissue types, but a comprehensive landscape of single-cell gene expression and cell types for humans has not been described.

Guoji Guo generated single-cell RNA sequencing data for 60 human tissue types, including both adult and fetal tissues. These data allow comparative analyses of cell types between organs and provide insights into how gene expression differs between individual cells during development. The authors compare their data to similar datasets created from mouse organs, which reveals conserved patterns of gene expression. They note that the study is limited by the small sample size of cells for each tissue, but suggest that their data offers the most comprehensive cell-type repertoire described for humans reported to date.