Single-cell multi-omics sequencing of human early embryos
© JUAN GARTNER/Science Photo Library/Getty
As a human embryo develops from a fertilized egg into a complex cluster of cells ready for implantation in the womb, the chemical tags adorning its DNA undergo a series of organizational changes.
A Peking University–led team has now profiled the nature of this epigenetic complexity down to the single-cell level in sperm, eggs and six stages of pre-implantation embryos. The detailed map of modifications to DNA and its spool-like coiling structures provides a vast informative resource for future mechanistic studies of early human development.
The researchers showed that DNA−protein complexes known as chromatin were most loosely packaged — allowing genes and regulatory elements to be more accessible and active — in eggs and in single-cell zygotes. Chemical alterations then prompted the chromatin to tighten its coils over the first few cell divisions before loosening again (and staying loose) after about four days of development.
- Nature Cell Biology 20, 847–858 (2018). doi: 10.1038/s41556-018-0123-2