DOI: 10.5061/dryad.3v3m004
title: Data from: Red carotenoids and associated gene expression explain colour variation in frillneck lizards

description: A longstanding hypothesis in evolutionary ecology is that red-orange
 ornamental colours reliably signal individual quality due to limited
 dietary availability and metabolic costs associated with their production,
 such as the bio-conversion of dietary yellow carotenoids to red
 ketocarotenoids. However, in ectothermic vertebrates, these colours can
 also be produced by self-synthesised pteridine pigments. As a consequence,
 the relative ratio of pigment types and their biochemical and genetic
 basis have implications for the costs and information content of colour
 signals; yet they remain poorly known in most taxonomic groups. We tested
 whether red and yellow-frilled populations of the frillneck lizard,
 Chlamydosaurus kingii, differ in the ratio of different biochemical
 classes of carotenoid and pteridine pigments, and examined associated
 differences in gene expression. We found that, unlike other squamate
 reptiles, red hues derive from a higher proportion of ketocarotenoids
 relative to both dietary yellow carotenoids and to pteridines. Whereas red
 frill skin showed higher expression of several genes associated with
 carotenoid metabolism, yellow frill skin showed higher expression of genes
 associated with steroid hormones. Based on the different mechanisms
 underlying red and yellow signals, we hypothesise that frill colour
 conveys different information in the two populations. More generally, the
 data expand our knowledge of the genetic and biochemical basis of colour
 signals in vertebrates.
description: Spectral reflectance of
 frill colour patchesSpectral reflectance of
 frill colour patches from 18 frillneck lizards (7 west form from Kununurra
 and 11 east form from Cairns) measured using an Ocean Optics (Dunedin, FL,
 USA) Jaz portable spectrometer. The probe was mounted in a RHP1 probe
 holder to maintain a constant angle (45°) and distance from the surface of
 the skin, and each measurement was expressed relative to a Spectralon 99%
 white reflectance standard (Labsphere, Inc., North Sutton, NH, USA). Three
 separate scans were averaged for each colour patch.kingii_spec_data.xlsxWeight normalised relative responses of metabolitesTo identify colour pigments, metabolites were extracted from five samples of each of west form red skin, west form dull skin, east form yellow skin and east form dull skin and compared to commercial standards. The two pigment classes (carotenoids and pteridines) were semi-quantified in separate liquid chromatography-Mass spectrometry (LC-MS) analyses. Peak signals obtained from the LC-MS analysis were normalized to the weight (as a proxy for biomass) of the skin tissue extracted.kingii_pigment_levels.xlsxDeconseq reference for removing residual mtDNA and rRNA readsSpecies specific database for the software Deconseq to remove residual mtDNA and rRNA reads.kingii_deconseq_reference_mtdna_rrna.fastaGene expression referenceSpecies specific reference for downstream mapping (for estimating gene expression with RSEM) consisting of 15,074 protein coding regions annotated for Pogona vitticeps (the closest con-familial species for which a fully annotated genome is available).kingii_gene_expression_reference.fastaGene expression resultsRelative expression levels of genes for each skin transcriptome estimated using RSEM and Bowtie2.kingii_gene_expression_results.zipTranscriptome assembliesSkin transcriptomes de novo assembled using Trinity.kingii_assemblies.zipx