In human cells, there are about 20,000 genes on a two-meter DNA strand—finely coiled up in a nucleus about 10 micrometers in diameter. By comparison, this corresponds to a 40-kilometer thread packed ...
Left: staining for H3K27me3, which marks inactive DNA, on a nucleus of a wildtype embryo consisting of two cells Right: staining for H3K27me3, which marks inactive DNA, on a nucleus of an embryo ...