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Measuring gene expression in individual cells is crucial for understanding the gene regulatory network controlling human embryonic development.Here we apply single-cell RNA-Seq analysis to human preimplantation embryos, primordial germ cells (hPGCs) , and human embryonic stem cells (hESCs).We also systematically profile the DNA methylome of human early embryos from the zygotic stage through to post-implantation.We show that the major wave of genome-wide demethylation is complete at the 2-cell stage, contrary to previous observations in mice.Moreover, the demethylation of the paternal genome is much faster than that of the maternal genome, and by the end of the zygotic stage the genome-wide methylation level in male pronuclei is already lower than that in female pronuclei.Finally, we also show that long interspersed nuclear elements (LINEs) or short interspersed nuclear elements (SINEs) that are evolutionarily young are demethylated to a milder extent compared to older elements in the same family and have higher abundance of transcripts, indicating that early embryos tend to retain higher residual methylation at the evolutionarily younger and more active transposable elements.Our work provides insights of critical features of the transcriptome and DNA methylome landscapes of human early embryos and germline cells,as well as the functional significance of DNA methylome to regulation of gene expression and repression of transposable elements.