The extra-embryonic area opaca plays a role in positioning the primitive streak of the early chick embryo.

ABSTRACT: Classical studies have established that the marginal zone, a ring of extra-embryonic epiblast immediately surrounding the embryonic epiblast (area pellucida) of the chick embryo, is important in setting embryonic polarity by positioning the primitive streak, the site of gastrulation. The more external extra-embryonic region (area opaca) was thought to have only nutritive and support functions. Using experimental embryology approaches, this study reveals three separable functions for this outer region. First, juxtaposition of the area opaca directly onto the area pellucida induces a new marginal zone from the latter; this induced domain is entirely posterior in character. Second, ablation and grafting experiments using an isolated anterior half of the blastoderm and pieces of area opaca sug

SUBMITTER: Lee HC 

PROVIDER: S-EPMC9270967 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature