Adaptive sequence evolution in a color gene involved in the formation of the characteristic egg-dummies of male haplochromine cichlid fishes.
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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DOI：
10.1186/1741-7007-5-51
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发表时间：
2007-11-15
期刊：
影响因子：
5.4
通讯作者：
Meyer A
中科院分区：
文献类型：
--
作者：
Salzburger W;Braasch I;Meyer A
东非异常多样化的慈鲷鱼群是平行适应辐射的主要例子。东非超过1800种特有的慈鲷物种中约有80%，以及维多利亚湖和马拉维湖的所有慈鲷物种，都属于一个进化特别迅速的谱系，即单染慈鲷。单色鱼的一个特征是它们在雄性的臀鳍上拥有假卵。这些卵点模仿真实的卵，并在这些母体口孵鱼的交配系统中发挥重要作用。在这里，我们表明单染色质的卵斑由黄色色素细胞、黄色素团组成，并且编码III型受体酪氨酸激酶、集落刺激因子1受体a（csf1ra）的基因在卵斑中表达组织。分子进化分析表明，csf1ra的胞外配体结合和受体相互作用域在单染物的祖先谱系中经历了适应性序列进化，与卵假模型的出现相一致。我们还发现，CSF1RA是在一个遥远的相关慈鲷物种，ectodine慈鲷Ophthalmotilapia腹，其中具有类似功能的标记进化的腹鳍收敛的haplochromines的蛋假人。我们的结论是，修改现有的信号转导机制可能已经演变的haplochromine血统与起源的臀鳍蛋假人。积极的选择过程中发挥作用的颜色基因，似乎参与了性选择性状的形态发生，蛋假人，突出了进一步调查的比较基因组基础的慈鲷鱼的表型多样化的重要性。
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. 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. 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.
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影响因子：
5.8
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