QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online May 2, 2008
Journal of Experimental Biology 211, 1559-1564 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.016048

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Gustafsson, O. S. E. Articles by Kröger, R. H. H. PubMed PubMed Citation Articles by Gustafsson, O. S. E. Articles by Kröger, R. H. H.

Early evolution of multifocal optics for well-focused colour vision in vertebrates

O. S. E. Gustafsson^1,*, S. P. Collin² and R. H. H. Kröger¹

¹ Department of Cell and Organism Biology, Lund University, Helgonavägen 3, 223 62 Lund, Sweden
² Marine Neurobiology Laboratory, School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Queensland, Australia

^* Author for correspondence (e-mail: Ola.Gustafsson{at}cob.lu.se)

Accepted 10 March 2008

Jawless fishes (Agnatha; lampreys and hagfishes) most closely resemble the earliest stage in vertebrate evolution and lamprey-like animals already existed in the Lower Cambrian [about 540 million years ago (MYA)]. Agnathans are thought to have separated from the main vertebrate lineage at least 500 MYA. Hagfishes have primitive eyes, but the eyes of adult lampreys are well-developed. The southern hemisphere lamprey, Geotria australis, possesses five types of opsin genes, three of which are clearly orthologous to the opsin genes of jawed vertebrates. This suggests that the last common ancestor of all vertebrate lineages possessed a complex colour vision system. In the eyes of many bony fishes and tetrapods, well-focused colour images are created by multifocal crystalline lenses that compensate for longitudinal chromatic aberration. To trace the evolutionary origins of multifocal lenses, we studied the optical properties of the lenses in four species of lamprey (Geotria australis, Mordacia praecox, Lampetra fluviatilis and Petromyzon marinus), with representatives from all three of the extant lamprey families. Multifocal lenses are present in all lampreys studied. This suggests that the ability to create well-focused colour images with multifocal optical systems also evolved very early.

Key words: longitudinal spherical aberration, longitudinal chromatic aberration, lens, multifocal, colour vision, evolution, lamprey