OR genes expression levels in the L. crocea olfactory epithelium. The expression levels of OR genes from different clades were determined by quantitative real-time PCR. Expression levels relative to the control gene β-actin were calculated using the standard curve method and are reported on a log10 scale. The letters a-k indicate clades.
Zhou et al. BMC Evolutionary Biology 2011 11:237 doi:10.1186/1471-2148-11-237