Progress and challenges in human developmental cell atlas.

Illustrating molecular mechanisms of human embryonic development has always been one of the most significant challenges in biology. The scarcity of human embryo samples, the difficulty in dissecting embryo samples, and the complex structures of human organs are the major obstacles in studying human embryogenesis. In recent years, with the rapid advancement of single-cell technology, humans can systematically analyze the dynamic changes in differentiation at various stages of the central dogma and achieve observation and research with spatial information. This has accelerated the progress in constructing a human developmental cell atlas, ultimately allowing us to depict the cell ontology, fate trajectories, and three-dimensional dynamic changes of human development. In this review, we first introduce the single-cell technologies used to construct the atlas, then summarize the latest progress in human developmental cell atlas, followed by identifying the main problems and challenges in this field so far. Finally, we discuss how to utilize the human developmental cell atlas to address key biological and medical issues. This review provides guidance for the optimal use of single-cell omics technology in constructing and applying a human developmental cell atlas.