Figure 6

Epigenetic pathways used to silence gene expression. SSCP analysis revealed that Gene 19 exhibited expression divergence; one copy in the BB subgenome was silenced but no genomic variation was found to affect transcription. We examined the 5′UTRs of this gene and found a hAT element inserted in the predicted promoter region only in the copy in the BB subgenome. We profiled the DNA methylation pattern for the 2 kb upstream from TSS of Gene 19 in the BB subgenome and found that the DNA methylation level was dramatically increased, which inhibited normal gene expression. Using the same approach, we examined the DNA methylation levels for the BB, BC_C and CC genomes, and heavy methylation levels were not found. The red dots represent cytosines, the x-axis represents the DNA sequence (or base position) and the y-axis represents the DNA methylation level (calculated as the number of methylated Cs divided by 20). Thus, each dot represents the methylation level of each cytosine.