Annals of morphology fields and prepatterns. Editorial Festschrift for John C. Carey, MD, MPH.

The investigation of mammalian malformations began to approach human needs in the 19th century with, for example, Meckel's dissection of sibs with the "Meckel" syndrome, his intimation of Heredität as cause of the condition, his conclusion as to the common causal origin of this specific combination of congenital anomalies, the clear enunciation of the concept of primary malformations, the recognition that many human malformations are normal developmental states in other animals, and that some were normal anatomical states in remote ancestors and now still normal in collateral descendants (atavisms, Darwin's "reversions"; for example, four wings in dipterans, normal in dragonflies and their common ancestor). Later in the century, Wilhelm His Sr. had proposed a schematic map of "organ-forming districts" for prospective chick development, a concept that did not sit well with early workers in developmental biology (e.g., Boveri) until methods became available for a direct experimental "attack" on the embryo. This approach was pioneered by Spemann and Mangold through interspecies transplantation of embryonic rudiments with the spectacular result that set the research stage in developmental biology for the next many years. But it was not until mid-century that the late, great geneticist, Curt Stern, made the His model of chick development more intellectually and experimentally approachable with his meticulous analysis of cuticular appendages of Drosophila, one bristle and one bristle group (field) at a time, in mosaics or gynandromorphs, leading to the ingenious concept of prepatterns. As a basic scientist, Stern did not broaden prepatterns into medicine or to human malformations where it has now found a most gratifying application. This contribution to the Carey Festschrift is to summarize, briefly, field and prepattern theory. © 2016 Wiley Periodicals, Inc.