[Research progress on methylation of histones H3K9 and H3K27 in early-stage embryos].

With the in-depth exploration of all stages in early-stage embryos, in particular zygotic genome activation and first cell lineage differentiation, researchers have found that early embryonic epigenetics follows a strict pattern of temporal and spatial modification. Previous studies have determined the inhibitory effect of H3K9me3 and H3K27me3 on genomic expression, and found that they are involved in many core biological events in the genome such as chromatin reprogramming, genomic imprinting, maintenance of embryonic stem cell pluripotency and somatic cell nuclear transfer, though the detailed molecular mechanism has remained elusive. From the point of developmental biology and epigenetics, this article has expounded the research progress on the methylation of H3K9 and H3K27 histones in early-stage embryos, which may provide a clue for the complex mechanism of embryonic development and improvement of culture method for embryos in vitro.