Ocular expression and genomic architecture of SWS2 and LWS in guppies and relatives. (A) Histograms of guppy opsin expression (mean = dashed line) from one- and two-month old juvenile and adult cDNA samples (shown in the same order as Figure 2A). Opsin transcript copy number was normalized to the geometric mean of three reference genes (asterisk): COI, β-actin, and Myosin-HC. Error bars (±S.E.M. of triplicate reactions) are shown for all samples. Colors represent the λmax of each opsin (based on Wavelength to RGB v.1.0 software). Expression (when known), genomic organization, and λmax data are shown for: adult and juvenile guppies (see text for opsin-to-λmax assignments) [8,28], adult green swordtail, X. helleri, (note SWS2A and P180 λmax assignments are uncertain ), adult medaka , and adult and juvenile zebrafish . Intergenic, candidate LCR, and exon/intron lengths are not to scale. (B) Location of S180r in intron XI of gephyrin (GPHN) in X. helleri  and guppy . Guppy S180r expression (right) adheres to the parameters described for panel A. S180r exon-intron lengths are to scale and are represented in number of base-pairs unless otherwise indicated (i.e., kilo-bases (Kb) used for large intronic sequences); data are from: references [8,35,41] and the present study.
Laver and Taylor BMC Evolutionary Biology 2011 11:81 doi:10.1186/1471-2148-11-81