establishes germline versus soma by balancing inherited histone methylation.

Formation of a zygote is coupled with extensive epigenetic reprogramming to enable appropriate inheritance of histone methylation and prevent developmental delays. In , this reprogramming is mediated by the H3K4me2 demethylase SPR-5 and the H3K9 methyltransferase, MET-2. In contrast, the H3K36 methyltransferase MES-4 maintains H3K36me2/3 at germline genes between generations to facilitate re-establishment of the germline. To determine whether the MES-4 germline inheritance pathway antagonizes reprogramming, we examined the interaction between these two pathways. We found that the developmental delay of mutant progeny is associated with ectopic H3K36me3 and the ectopic expression of MES-4-targeted germline genes in somatic tissues. Furthermore, the developmental delay is dependent upon MES-4 and the H3K4 methyltransferase, SET-2. We propose that MES-4 prevents crucial germline genes from being repressed by antagonizing maternal reprogramming. Thus, the balance of inherited histone modifications is necessary to distinguish germline versus soma and prevent developmental delay.This article has an associated 'The people behind the papers' interview.