Ultraviolet pigments in birds evolved from violet pigments by a single amino acid change

Abstract

UV vision has profound effects on the evolution of organisms by affecting such behaviors as mating preference and foraging strategies. Despite its importance, the molecular basis of UV vision is not known. Here, we have transformed the zebra finch UV pigment into a violet pigment by incorporating one amino acid change, C84S. By incorporating the reverse mutations, we have also constructed UV pigments from the orthologous violet pigments of the pigeon and chicken. These results and comparative amino acid sequence analyses of the pigments in vertebrates demonstrate that many avian species have achieved their UV vision by S84C.

Opening the “Black Box”: The Genetic and Biochemical Basis of Eye Evolution

“…Turning on expression of spam in an eye with a normally closed rhabdome spread the photoreceptor cells apart, effectively causing an open rhabdome eye by mis-expression of this one gene. These results are consistent with spam expression as having causal role in the evolution of open rhabdoms from closed rhabdoms (Zelhof et al 2006).…”

“…Amino acid changes in opsins modulate the wavelength (color) sensitivity of the protein/chromophore complex. Among several bird species, Yokoyama et al (2000) found a correlation between wavelength sensitivity and which amino acid is present at a particular site in the opsin protein. Three birds with UV vision have cysteine amino acids in position 84 (C84) of one of their opsin genes.…”

“…Such a correlation suggests a causal relationship between the amino acid at position 84 of opsin, and the color sensitivity of that opsin. Increasingly, biologists are able to test explicitly hypotheses based on correlation, that a given molecular change is the cause of a phenotypic change: Yokoyama et al (2000) were able to do just this. They experimentally altered C84 to S84 in the opsin protein of a zebra finch.…”

“…Open rhabdomes, where photoreceptor cells that are spread out within each facet of the eye, as opposed to tightly packed, are present in the compound eye of flies. The open rhabdome is associated with expression of the gene eyes shut, also called spam (Husain et al 2006;Zelhof et al 2006). This correlation was tested by mis-expression of the spam gene in an eye with tightly packed receptors.…”

Genetic architecture underlying convergent evolution of egg-laying behavior in a seed-feeding beetle

“…An unresolved question is the frequency with which such convergence reflects parallel genetic mechanisms (Arendt and Reznick 2008;Wood et al 2005;Zhang and Kumar 1997). For traits strongly influenced by one or a few genes, convergence may require little genetic modification, and homoplasy could arise from similar or even identical sequence-level changes (Colosimo et al 2005;Odeen and Hastad 2003;Yokoyama et al 2000). Many ecologically important traits are influenced by multiple loci, however, and their evolution will depend on covariances with other fitness components as well as genotype-by-environment interactions (Forister et al 2007;Mackay and Anholt 2007).…”