I've always been wondering how cells "know" where they're supposed to move.
His lab has shown functioning eyes on the backs of tadpoles, allowed frog leg regeneration where none existed, and performed several other modifications that change the communication between cells to trigger desired growth. Surprisingly, the interventions are point modifications, then the system handles the rest of the process.
Cell-to-cell communication has a lot of explanatory power for a cell (or collection of cells) "knowing what/where to be".
"I wish my high school biology teacher had asked the class how an embryo could possibly differentiate—and then paused to let us really think about it. The whole subject is in the answer to that question. A chemical gradient in the embryonic fluid is enough of a signal to slightly alter the gene expression program of some cells, not others; now the embryo knows “up” from “down”; cells at one end begin producing different proteins than cells at the other, and these, in turn, release more refined chemical signals; ...; soon, you have brain cells and foot cells."
But it could still be a useful answer depending on the viewpoint of the person asking and what they were hoping to learn.
The only difference is today's biologists have replaced God with DNA - the almighty molecule that knows everything about humans.