Gardner R L, Rossant J
J Embryol Exp Morphol. 1979 Aug;52:141-52.
Two distinct patterns of chimaerism were found in conceptuses produced by injecting dissociated 4.5-day inner cell mass cells into genetically dissimilar blastocysts. Pattern 1: donor cells were found in the endoderm layer of the visceral yolk sac, but not in the adjacent mesoderm layer of this organ or in the foetus itself. Pattern 2: donor cells were found in the mesoderm layer of the visceral yolk sac and/or foetus, but never in the yolk-sac endoderm as well. Primitive endoderm cells of donor inner cell masses are responsible for the first pattern and primitive ectoderm cells for the second. These results, together with those of previous studies, suggest that the entire foetus, including its endodermal components, is formed from the primitive ectoderm, and that primitive endoderm forms only extra-embryonic endoderm of the conceptus.
将解离的4.5天龄内细胞团细胞注射到基因不同的囊胚中，在由此产生的胚胎中发现了两种不同的嵌合模式。模式1：在内脏卵黄囊的内胚层中发现了供体细胞，但在该器官相邻的中胚层或胎儿本身中未发现。模式2：在内脏卵黄囊和/或胎儿的中胚层中发现了供体细胞，但从未在卵黄囊内胚层中发现。供体内细胞团的原始内胚层细胞导致第一种模式，原始外胚层细胞导致第二种模式。这些结果与先前研究的结果一起表明，整个胎儿，包括其内胚层成分，均由原始外胚层形成，并且原始内胚层仅形成胚胎的胚外内胚层。
