Borrowing thy neighbour's genetics: neural induction and a Brachyury mutant in Xenopus

A recent article by Rao exemplifies a number of new trends in developmental biology, both of technical strategy and approach to the problem of neural induction. Rao introduced into frog embryos a mutant form of a mesodermal gene, Brachyury, and caused ectopic neural differentiation. This essay traces the route from the original Brachyury mutation in mouse to the most likely conclusion of Rao's experiments--suggested previously--that neural fate is a default pathway.