Pattern formation in hydra tissue without developmental gradients

摘要: Abstract Ring-shaped pieces of hydra tissue were excised from a specified position on body column 20–30 polyps and grafted together in tandem like chain beads. A “tandem graft” prepared this way has the same basic organization tube-like morphology as normal column, but lacks head, foot, developmental gradients ordinarily present. Three major types structures formed along length graft: heads, buds, feet. The relative number these produced was strongly affected by origin used to prepare graft. Evidence obtained which suggests that originally located outside budding zone intact strong latent capacity form bud, level forms gradient toward hypostome. also is consistent with view head foot forming mechanisms cross-react positively, increasing chances for two be next each other