Figure 4. Heritability of Polymorphic Gene Methylation.

The gene At4g28850 is methylated in Col but not Ler. Genomic DNA was prepared from F ₁ and F ₂ siblings derived from reciprocal crosses between Col and Ler and subjected to McrBC digestion and PCR amplification of this locus as in Figure 1. The amplification product (tb63b02) has a small deletion in Ler, enabling the parental alleles to be distinguished. DNA samples were digested (+) or mock-digested (−) with McrBC. Control primers were used to amplify a methylated retrotransposon (TA2) in each sample, as well as an unmethylated control tile (ta25c11). Samples of two F ₁ and ten F ₂ plants are shown for each cross (out of a total of eight and 40, respectively) (Table S3). In almost all cases, the Col allele is digested by McrBC, and the Ler allele is never digested. Two exceptions are indicated (a and b) in which the Col allele has lost all or most of its associated methylation.