Expression from both alleles is generally observed in analyses of diploid cell populations, but studies addressing allelic expression patterns genome-wide in single cells are lacking. Here, researchers at the Ludwig Institute for Cancer Research, Sweden present global analyses of allelic expression across individual cells of mouse preimplantation embryos of mixed background (CAST/EiJ × C57BL/6J). They discovered abundant (12 to 24%) monoallelic expression of autosomal genes and that expression of the two alleles occurs independently. The monoallelic expression appeared random and dynamic because there was considerable variation among closely related embryonic cells. Similar patterns of monoallelic expression were observed in mature cells. Their allelic expression analysis also demonstrates the de novo inactivation of the paternal X chromosome. The researchers conclude that independent and stochastic allelic transcription generates abundant random monoallelic expression in the mammalian cell.
Single-cell RNA-seq reveals dynamic, random monoallelic gene expression
Deng Q, Ramsköld D, Reinius B, Sandberg R. (2014) Single-cell RNA-seq reveals dynamic, random monoallelic gene expression in mammalian cells. Science 343(6167), 193-6. [abstract]