“

What we've been able to tease out from the mathematical model is it's not necessarily that these cells are migrating in a directed way, actually these cells are diffusing, there's no direction to their migration. It's like when you put a drop of milk into a cup of coffee that you haven't stirred. Eventually that milk will be spread evenly throughout your coffee, and these cells are doing the same sort of thing - they're moving in an undirected manner and eventually, slowly, they manage to fully colonize the skin of this animal.