<i>Mop2-1/Mop2-1</i> prevents establishment of <i>p1</i> paramutation^a.

a Paramutation at p1 is observed in the pericarp (seed coat), where the paramutable P1-rr allele specifies dark red pericarp pigment. When paramutated, by exposure to paramutagenic P1-rr' and the P1.2b::GUS transgene (transgenic event P2P147-37, [13]), pigmentation of paramutable P1-rr is reduced to colorless or light patterned pericarp. Details of experiment are in Figure S4. b Molecular genotyping was used to determine the Mop2-1 genotype. c The negative pleiotropic developmental phenotypes in Mop2-1 homozygotes result in frequent abortion of ears resulting in only a small number of Mop2-1/Mop2-1 homozygous ears that can be pollinated and produce sufficient seed to score the p1 pigment in mature ears.