DOI: 10.5061/dryad.f8584
title: Data from: A cure for the blues: opsin duplication and subfunctionalization for short-wavelength sensitivity in jewel beetles (Coleoptera: Buprestidae)

description: Background: Arthropods have received much attention as a model for
 studying opsin evolution in invertebrates. Yet, relatively few studies
 have investigated the diversity of opsin proteins that underlie spectral
 sensitivity of the visual pigments within the diverse beetles (Insecta:
 Coleoptera). Previous work has demonstrated that beetles appear to lack
 the short-wavelength-sensitive (SWS) opsin class that typically confers
 sensitivity to the “blue” region of the light spectrum. However, this is
 contrary to established physiological data in a number of Coleoptera. To
 explore potential adaptations at the molecular level that may compensate
 for the loss of the SWS opsin, we carried out an exploration of the opsin
 proteins within a group of beetles (Buprestidae) where short-wave
 sensitivity has been demonstrated. RNA-seq data were generated to identify
 opsin proteins from nine taxa comprising six buprestid species (including
 three male/female pairs) across four subfamilies. Structural analyses of
 recovered opsins were conducted and compared to opsin sequences in other
 insects across the main opsin classes—ultraviolet, short-wavelength, and
 long-wavelength. Results: All nine buprestids were found to express two
 opsin copies in each of the ultraviolet and long-wavelength classes,
 contrary to the single copies recovered in all other molecular studies of
 adult beetle opsin expression. No SWS opsin class was recovered.
 Furthermore, the male Agrilus planipennis (emerald ash borer—EAB)
 expressed a third LWS opsin at low levels that is presumed to be a larval
 copy. Subsequent homology and structural analyses identified multiple
 amino acid substitutions in the UVS and LWS copies that could confer
 short-wavelength sensitivity. Conclusions: This work is the first to
 compare expressed opsin genes against known electrophysiological data that
 demonstrate multiple peak sensitivities in Coleoptera. We report the first
 instance of opsin duplication in adult beetles, which occurs in both the
 UVS and LWS opsin classes. Through structural comparisons of known insect
 opsins, we suggest that opsin duplication and amino acid variation within
 the chromophore binding pocket explains sensitivity in the
 short-wavelength portion of the visible light spectrum in these species.
 These findings are the first to reveal molecular complexity of the color
 vision system within beetles.
description: Lord_etal_2015_BupOpsinAlignmentTotalAmino acid alignment file (FASTA format) of all opsin data used in the reconstruction of the total opsin topology.Lord_etal_2015_BupOpsinAlignmentUVAmino acid alignment file (FASTA format) of ultraviolet-sensitive opsin data used in the reconstruction of the UVS opsin topology.Lord_etal_2015_BupOpsinAlignmentLWAmino acid alignment file (FASTA format) of long wavelength-sensitive opsin data used in the reconstruction of the LWS opsin topology.Lord_etal_2015_Bup_OpsinAlignment_nucl_PStestsNucleotide alignment file of all opsin data used in the positive selection analyses.