Question

What is the differential adhesion hypothesis (think "surface tension") and why it is important?

Answer 1

Steinberg proposed a differential adhesion hypothesis, also called as thermodynamic model. It states that sorting of cell sorting depends on surface tension. Surface tension equals strength of adhesion. Therefore, more adhering cells will be surrounded by less strongly adhering cells

It is important because:

Surface tension means tendency of surface of fluid to shrink, so that minimum surface area is used. Therefore, it minimizes the overall energy of the system.

Cells adhere to one another with different strengths. Then they rearrange and forms a adhesive energy having less surface area.

More cell-cell adhesion causes higher surface tension between cells which means more cohesion between cells.
It explains patterns of sorting of cell based on thermodynamic principles. Cells interacted to form an aggregate which is most thermodynamically stable

Cell sorting in order of decreasing surface tensions. The cells having more surface cohesion migrated centrally than those cells having
less surface tension.