Adaptive sequence evolution in a color gene involved in the formation of the characteristic egg-dummies of male haplochromine cichlid fishes.

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Serval ID
serval:BIB_7E0B4F262EC1
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Adaptive sequence evolution in a color gene involved in the formation of the characteristic egg-dummies of male haplochromine cichlid fishes.
Journal
BMC Biology
Author(s)
Salzburger W., Braasch I., Meyer A.
ISSN
1741-7007[electronic], 1741-7007[linking]
Publication state
Published
Issued date
2007
Volume
5
Pages
51
Language
english
Abstract
BACKGROUND: The exceptionally diverse species flocks of cichlid fishes in East Africa are prime examples of parallel adaptive radiations. About 80% of East Africa's more than 1 800 endemic cichlid species, and all species of the flocks of Lakes Victoria and Malawi, belong to a particularly rapidly evolving lineage, the haplochromines. One characteristic feature of the haplochromines is their possession of egg-dummies on the males' anal fins. These egg-spots mimic real eggs and play an important role in the mating system of these maternal mouthbrooding fish. RESULTS: Here, we show that the egg-spots of haplochromines are made up of yellow pigment cells, xanthophores, and that a gene coding for a type III receptor tyrosine kinase, colony-stimulating factor 1 receptor a (csf1ra), is expressed in egg-spot tissue. Molecular evolutionary analyses reveal that the extracellular ligand-binding and receptor-interacting domain of csf1ra underwent adaptive sequence evolution in the ancestral lineage of the haplochromines, coinciding with the emergence of egg-dummies. We also find that csf1ra is expressed in the egg-dummies of a distantly related cichlid species, the ectodine cichlid Ophthalmotilapia ventralis, in which markings with similar functions evolved on the pelvic fin in convergence to those of the haplochromines. CONCLUSION: We conclude that modifications of existing signal transduction mechanisms might have evolved in the haplochromine lineage in association with the origination of anal fin egg-dummies. That positive selection has acted during the evolution of a color gene that seems to be involved in the morphogenesis of a sexually selected trait, the egg-dummies, highlights the importance of further investigations of the comparative genomic basis of the phenotypic diversification of cichlid fishes.
Keywords
Adaptation, Physiological, Animals, Chromatophores/physiology, Cichlids/genetics, Cichlids/physiology, Evolution, Molecular, Gene Expression, In Situ Hybridization, Macrophage Colony-Stimulating Factor/genetics, Male, Ovum, Phylogeny, Pigmentation/genetics, Receptor Protein-Tyrosine Kinases/genetics, Receptors, Colony-Stimulating Factor/genetics, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Sex Characteristics
Pubmed
Web of science
Open Access
Yes
Create date
07/10/2010 13:43
Last modification date
20/08/2019 14:39
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