Photoreceptor distributions, visual pigments and the opsin repertoire of Atlantic halibut (Hippoglossus hippoglossus)
Date
2022
Authors
Bolstad, Kennedy
Flamarique, Iñigo Novales
Journal Title
Journal ISSN
Volume Title
Publisher
Scientific Reports
Abstract
Fishes often have cone photoreceptors organized in lattice-like mosaic formations. In flatfishes, these
lattices undergo dramatic changes during metamorphosis whereby a honeycomb mosaic of single
cones in the larva is replaced by a square mosaic of single and double cones in the adult. The spatiotemporal
dynamics of this transition are not well understood. Here, we describe the photoreceptors
and mosaic formations that occur during the larva to juvenile transition of Atlantic halibut from the
beginning of eye migration to its completion. To gauge the possibility of colour vision, visual pigments
in juveniles were measured by microspectrophotometry and the opsin repertoire explored using
bioinformatics. At the start of eye migration, the larva had a heterogeneous retina with honeycomb
mosaic in the dorsonasal and ventrotemporal quadrants and a square mosaic in the ventronasal and
dorsotemporal quadrants. By the end of metamorphosis, the square mosaic was present throughout
the retina except in a centrodorsotemporal area where single, double and triple cones occurred
randomly. Six cone visual pigments were found with maximum absorbance (λmax, in nm) in the short
[S(431) and S(457)], middle [M(500), M(514) and M(527)], and long [L(550)] wavelengths, and a rod
visual pigment with λmax at 491 nm. These pigments only partially matched the opsin repertoire
detected by query of the Atlantic halibut genome. We conclude that the Atlantic halibut undergoes
a complex re-organization of photoreceptors at metamorphosis resulting in a multi-mosaic retina
adapted for a demersal life style.
Description
Keywords
Nervous system, Retina, Sensory systems, Visual system
Citation
Bolstad, K. & Flamarique, I. N. (2022). “Photoreceptor distributions, visual pigments and the opsin repertoire of Atlantic halibut (Hippoglossus hippoglossus).” Scientific Reports, 12(8062). https://doi.org/10.1038/s41598-022-11998-9