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Studies on limb morphogenesis. VI. Experiments with early stages of the polydactylous mutant eudiplopodia

✍ Scribed by Fraser, Robert A. ;Abbott, Ursula K.


Publisher
John Wiley and Sons
Year
1971
Tongue
English
Weight
808 KB
Volume
176
Category
Article
ISSN
0022-104X

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✦ Synopsis


Abstract

Prospective limb mesoderm was transplanted to the flank of twoday host embryos in efforts to study tissue specific effects of the avian polydactylous mutant, eudiplopodia. Initially, normal limb mesoderm was placed in the flank of two‐day scaleless hosts and a scaleless limb resulted, ensuring that the regenerating host ectoderm provided the epithelial covering for the graft limb. Eudiplopod limbs developed from grafts of normal mesoderm to two‐day eudiplopod hosts while the reciprocal combination produced normal limbs. Similar transplants showed that eudiplopod ectoderm may respond to leg mesoderm from both quail and talpid^2^ embryos and does so typically by forming two ridges. Grafts of normal limb mesoderm to three‐and‐one‐half‐day eudiplopod hosts produced supernumerary limbs in the majority of cases whereas most grafts to normal hosts of similar age produced only a skin covered nodule.

It is concluded that the mutant gene extends the time of ectodermal competence for ridge formation and that as a consequence of this specificity the mutant effects are seen only in eudiplopod limb ectoderm.