Practice question

Early embryos interact extensively with their surroundings, and fate is assessed operationally through isolation in neutral media. When cells are removed to a noninstructive environment they differentiate autonomously according to specification already acquired, expressing lineage markers. In intact embryos compensation frequently occurs after cell loss because remaining cells receive redistributed inductive signals and respecify accordingly, characteristic of regulative development. Predetermined fate from fertilization applies only to highly mosaic systems. Therefore specification is defined by capacity for autonomous differentiation in neutral conditions while still retaining responsiveness to community influences and external gradients.