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Visual demonstration of the limb‐forming zone in the chick embryo lateral plate
Author(s) -
Stephens Trent D.,
Sanders Duane D.,
Yap Clementine Y. F.
Publication year - 1992
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1052130304
Subject(s) - ectoderm , apical ectodermal ridge , biology , anatomy , flank , limb development , embryo , limb bud , lateral plate mesoderm , intermediate mesoderm , mesoderm , zone of polarizing activity , thickening , embryogenesis , microbiology and biotechnology , embryonic stem cell , materials science , gastrulation , polymer science , gene , biochemistry
The present study was undertaken to determine whether a visible Wolffian ridge, distinct from the lateral fold, can be identified in chick embryos. Ectoderm thickness was measured in stage 11–17 chick embryos. There was a general trend, from thin ectoderm in the midline, to an ectodermal thickening over the somites, intermediate mesoderm, and lateral plate. Other embryos were cut from the yolk, pinned out, and photographed. The lateral fold was then eliminated, and the embryo was rephotographed. The photographs reveal a definite opaic zone, distinct from the lateral fold, in stage 11–18 chick embryos. Furthermore, there is a direct correlation between the opacity of this cellular band and the limb‐forming potential of grafted wing, flank, and leg regions (see Stephens et al., '89). At stages 11–14, the wing, flank, and leg exhibit a uniform opacity, and a uniform capacity for limb formation when grafted to a host celom. From stage 15 to stage 18, the opacity in the flank diminishes, and its limb‐forming capability disappears. This study demonstrates the presence of an opaic zone, which we have called the limb‐forming zone (LFZ) along the lateral side of early chick embryos, which is independent of the lateral fold, is not as extensive as the lateral plate, and is not simply associated with ectodermal thickening, but which is directly correlated with limb‐forming potential in the lateral plate. © 1992 Wiley‐Liss, Inc.