Extra Epigenetic Packaging Keeps Egg Cells Fresh

A type of epigenetic mark that ordinarily causes gene activation may instead facilitate gene silencing in oocytes, cells that must be kept in stasis throughout childhood if they are to have the ability to contribute to new life in a woman’s adulthood. The mark, called histone 3 K4 trimethylation (H3K4me3), appears to exert its different effects—focused activation or widespread inactivation—depending on how it is distributed in the genome.According to scientists based at the Bab