Lineage specific trimethylation of H3 on lysine 4 during C. elegans early embryogenesis

► This study surveys epigenetic marks in the early C. elegans embryo. ► We found that H3K4me3 is almost undetectable in germline blastomeres. ► We also found that a limited number of somatic blastomeres are devoid of H3K4me3. ► H3K4me3 is deposited by the MLL complex and antagonised by PIE-1 > Embryonic H3K4me3 deposition is a dynamic and highly regulated process.