1. The biological theory that an organism develops gradually from an undifferentiated egg or embryo through the formation of new structures, rather than from a preformed miniature version.
Usage: biology; developmental biology; historical scientific theory
2. The study of how environmental factors and gene expression influence the development and function of organisms without changing the underlying DNA sequence.
Usage: modern biology; genetics

Examples

• The theory of epigenesis challenged the earlier belief that organisms were fully formed in miniature inside the egg.
• Scientists studying epigenesis discovered that development involves the gradual emergence of complexity from simpler structures.
• Modern epigenesis research shows how diet and stress can affect gene expression across generations.
• The concept of epigenesis was revolutionary in explaining how a single cell could give rise to an entire organism.
• Epigenesis demonstrates that development is not predetermined but shaped by interactions between genes and environment.
• Researchers use epigenesis to understand how identical twins can develop different traits despite sharing the same DNA.