The inactive X chromosome ( Xi) was hypermethylated at only a subset of gene-rich regions and, unexpectedly, overall hypomethylated relative to its active counterpart.

• 失活的X染色体仅在富含基因区域的一部分具有高甲基化，而且出人意料的是，所有低甲基化的区域都对应于其活性的副本。