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Evidence that mesodermal migration does not occur during human gastrulation (DREM databases utilization # 2)
Author(s) -
Gasser Raymond Frank
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.471.3
Subject(s) - epiblast , primitive streak , gastrulation , biology , embryo , ingression , mesoderm , anatomy , microbiology and biotechnology , embryogenesis , embryonic stem cell , genetics , gene
The objective was to determine in human embryos if the changing positions of mesodermal cells from the primitive (gastrulation) streak result from migration between the overlying epiblast and underlying hypoblast layers as described in embryology books or if their changing positions result from cell proliferation and changes in the size and shape (growth movements) of the embryo. Embryos rapidly change in size and shape during the period when mesodermal migration is supposed to occur. Reconstructions were made from digital images of serial sections of Carnegie specimens at representative periods during gastrulation (stages 6‐9). Magnifications were kept identical. The caudal end of the primitive streak was used as the reference point because it ends close to the relatively stationary connecting stalk. The reconstructions were superimposed revealing that the changing positions of the mesodermal cells result from growth movements of the whole embryo together with cell proliferation. Rather than mesodermal cells moving from one region to another (migration) the study showed that they remain in the same region and move as the entire embryo enlarges and changes shape. The study found that cells in all three layers proliferate rapidly with the conclusion that mesodermal cell migration during gastrulation between the epiblast and hypoblast layers is unnecessary and does not occur. Supported by NIH grant RO1 HD 37811.