Morphological and molecular analysis of the early developing chick requires an expanded series of primitive streak stages.

摘要: A detailed analysis of the gastrulating chick embryo was performed using three methods : time-lapse videotaping embryos in culture, histological semithin sections, and situ hybridization with 10 mRNA signals expressed during gastrulation. The results suggest that gene expression pattern Goosecoid, Hex, Crescent, Bmp7 may be involved axial establishment temporal spatial arrangement cells forming prechordal plate endoderm, Chordin, cNot1, Noggin, Brachyury are precocious markers coming from Hensen's node, which contribute to rostralmost tip notochord, its arrowhead, head process, and, later, elongating notochord. These explain several earlier descriptions based only on morphological analyses mesodermal structures characteristic gastrulation stages. data, carefully observed compared whole-mount observation video, show changes cell populations, movements, differentiation occur step-by-step over a precise range, requires subdivision stages usually employed. Knowledge new aspects avian gastrulation, including patterns, immunocytochemical analyses, great number recent experiments microinjections or transplants groups analyze processes induction regulation, need support precisely defined scheme primitive streak (PS-stages), correlation these other approaches provide finer resolution staging steps, thus facilitate better understanding initial period. J. Morphol. © 2005 Wiley-Liss, Inc.