Differentiation of H3K4me2 from H3K4me3

Cited from Histone H3 Lys 4 methylation: caught in a bind?

Both H3K4me2 and H3K4me3 are found predominantly on active loci, although H3K4me3 occurs concomitantly with active transcription, while H3K4me2 can be present on poised, inactive genes.

Usually, H3K4me2 and H3K4me3 both peak at the transcription start site. Recent evidence suggests that H3K4me3 occurs after the general transcription machinery assembles on the promoter.