Eli5: How do bones and other organs know what shapes to grown into?

Question

Eli5: How do bones and other organs know what shapes to grown into?

In: 3675

Answer 1

Imagine you are making a map. As the map grows you need to figure out borders between countries. So you make a system to say where and when things have to change. Cells in the embryo, specifically stem cell, start to trade information with other cells to tell each other where on the map they think they are. The dna in the cells combined with the signals they receive from neighbors combined with markers blocking or allowing access to the dna tell cells what type of cell they need to develop into. It’s basically a very well orchestrated game of telephone.