Assorted chromatin modifications are not required for imprinted p4-siRNA production in endosperm.

Small RNAs were isolated from inter-ecotype crosses between wild type and a histone modification mutant and parental origin of small RNA was determined as described in figure 1. Accumulation of p4-siRNAs from paternal chromosomes was not induced when the Polycomb Repressive Complex 2 mutant fertilization independent endosperm (fie) was transmitted paternally. Likewise, mutations in histone deacetylase 6 (hda6), the H3K9 methyltransferase kryptonite (kyp), and the nucleosome remodeling proteins decrease in dna methylation 1 (ddm1) and morpheus' molecule 1 (mom1) did not affect uniparental expression of p4-siRNAs.