Practice question

Genetic specificity concept in induction was elegantly demonstrated through interspecies organizer grafts between newt and frog embryos performed by Holtfreter, Mangold and Spemann. Transplanted newt dorsal lip into frog ventral region induced secondary neural axis composed predominantly of host frog cells, but morphogenetic movements and cytodifferentiation reflected host genome and developmental tempo, not donor. This indicated inducing signal is broadly conserved and permissive across species, while execution of induced program depends on responder's own genetic information. Experiment distinguished true induction activating intrinsic patterning genes from self-differentiation of donor implant tissue directly.