Genome-wide expression analysis of embryonic development provides information that is useful in a variety of contexts. Here, we report transcriptome profiles of human early embryos covering development during the first third of organogenesis. We identified two major categories of genes, displaying gradually reduced or gradually increased expression patterns across this developmental window. The decreasing group appeared to include stemness-specific and differentiation-specific genes important for the initiation of organogenesis, whereas the increasing group appeared to be largely differentiation related and indicative of diverse organ formation. Based on these findings, we devised a putative molecular network that may provide a framework for the regulation of early human organogenesis. Our results represent a significant step in characterization of early human embryogenesis and provide a resource for understanding human development and for stem cell engineering.

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