Patterning of Mesenchyme - PMC Transplants

The results of reciprocal PMC transplants are quite clear: the ectoderm seems to provide much of the basic information used by primary mesenchyme as they form patterned skeletal elements. We know this because PMCs from nickel treated embryos are able to adopt a normal pattern when placed into a normal ectodermal shell. This is a nice demonstration of the general principle that local patterning cues in the environment are used by freely migrating cells as they move, and eventually stop in specific locations in the early embryo.