Examination of gene expression in human placenta using RNA-seq

As genome-scale DNA methylation sequencing technologies have improved it has become apparent that tissue-specific methylation can occur not only at promoters, enhancers, and CpG islands but also over larger genomic regions. In most human tissues, the vast majority of the genome is highly methylated (>70%). However, genomic sequencing of bisulfite-treated DNA (MethylC-seq) has revealed large partially methylated domains (PMDs) in some human cell lines. However, to date only cultured cells and some cancers have shown evidence for PMDs, suggesting that PMDs may not be observed in normal human tissues. Here we performed MethylC-seq in a set of human tissues and found that full-term human placenta shows clear evidence of PMDs. Examination of gene expression in human placenta using RNA-seq, with one biological replicate (taken from same placenta)