Eli5: How does a single cell multiply into exact copies of itself yet somehow knows to start building into different body parts? They are all in the same environment with the same DNA yet behave differently.

Question

Eli5: How does a single cell multiply into exact copies of itself yet somehow knows to start building into different body parts? They are all in the same environment with the same DNA yet behave differently.

In: Biology

Answer 1

Epigenetics. The cell has different *structures*, and based on the structures of both the cell and its neighbors, it knows what DNA to activate, and which cell type to become. Cells know which cell type to become based on what the cells around them are, and what stage in development they are in.