Fig. 1.

Directional regulatory change between Saccharomycetes in the membrane protein regulon. Each colored element represents regulatory changes between Saccharomyces cerevisiae and S. paradoxus in rich-medium (Tirosh et al. 2009) at one membrane protein gene, overlaid on a cartoon localization of the encoded protein. P, proportion of randomly sampled gene groups showing regulatory changes whose directions were at least as coherent as those observed in the membrane regulon (table 1). (A) Signs of cis-regulatory effects. Orange, the allele from S. paradoxus was the most highly expressed in an interspecific hybrid; blue, the S. cerevisiae allele was most highly expressed. (B) Signs of trans-regulatory effects, which derive from expression measurements of interspecific hybrids and of parental strains grown independently (Tirosh et al. 2009). Orange, the regulatory allele from S. paradoxus was associated with higher expression; blue, the S. cerevisiae allele was associated with higher expression.