Fig. 4

Pairwise comparisons of differentially expressed genes in the drought-shock treatment among the tissue types of the focal species. Each point represents the absolute expression level of a gene/cluster for both species being compared. The dashed black line is the expected line (slope = 1) if the two species expressed all loci at identical levels and informs whether one species/tissue is mounting a greater response than the other. The solid black line is the best fit line for the data given a linear model and tells us where the majority of the points lay. All solid black slopes were significantly different than 1 at alpha = 0.05 (P < 0.001). The grey open circles indicate a log-fold change less than 2, and the solid black circles indicate a log-fold change of 2 or greater. In all comparisons, the species that occurs in the more arid habitat is placed on the y-axis