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


Autoria(s): Salzburger W.; Braasch I.; Meyer A.
Data(s)

2007

Resumo

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.

Identificador

http://serval.unil.ch/?id=serval:BIB_7E0B4F262EC1

isbn:1741-7007[electronic], 1741-7007[linking]

pmid:18005399

doi:10.1186/1741-7007-5-51

isiid:000253594200001

http://my.unil.ch/serval/document/BIB_7E0B4F262EC1.pdf

http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_7E0B4F262EC12

Idioma(s)

en

Direitos

info:eu-repo/semantics/openAccess

Fonte

BMC Biology, vol. 5, pp. 51

Palavras-Chave #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
Tipo

info:eu-repo/semantics/article

article