Chromosome methylation patterns during mammalian preimplantation development

DNA methylation patterns in preimplantation mouse development have been studied by analysis of monoclonal antibody-to-5-methylcytosine (5-MeC) binding on metaphase chromosomes. At each cell stage certain chromosome patterns appeared. It appears that chromosome demethylation is associated with each DNA replication. A passive mechanism appears to be predominant in early development.