Figure 4

The 12 possible differential expression states in the somatic hybrid relative to its diploid parents. Roman numerals indicate the same categorization as used in Rapp et al. (2009), with figures schematizing their respective gene expression pattern for diploid parent G. arboreum (Ga: A-genome), tetraploid somatic hybrid (G.arboreum + G.stocksii: AS, AE genome) and diploid parent G. stocksii (Gs: E-genome). Additivity (I and XII), E-expression level dominance (II and XI), A-expression level dominance (IV and IX), transgressive expression lower than either parent (III, VII and X) or transgressive expression higher than either parent (V, VI and VIII).