Fig. 3From: Positive selection at sites of chemosensory genes is associated with the recent divergence and local ecological adaptation in cactophilic DrosophilaDistribution of the sites showing evidence of positive selection by protein domains in each chemoreceptor gene: Cytoplasmic (Cyto), Extracellular (Extr) and Transmembrane (Trans). The number of sites under positive selection was significantly higher in the cytoplasmic region (Tukey test for multiple comparisons; p < 0.05)Back to article page