Principles of human development and germ cell program

Primordial germ cells (PGCs), the precursors of eggs and sperm, emerge in the human embryo on day 17 of development, while the surrounding cells develop into somatic tissues of the body. Tracing the origin and development of PGCs will reveal the organisation of the early human embryo. At fertilisation, germ cells pass on about 20,000 genes, the blueprint for development, and non-genetic information that can regulate gene expression. They are critical for how the brain and other organs develop and function. The transfer of this information from parent to offspring by the ‘immortal’ germline is repeated for every generation and has consequences for human health and disease. Germ cells undergo extensive reprogramming which rejuvenates the lineage and is essential for their distinctive potency. By contrast, somatic tissues become prone to age-related diseases.

Detailed understanding of the mechanism of germline reprogramming might provide approaches to address age-related diseases in bodily tissues.