Evolutionary relationships among copies of feather beta (β) keratin genes from several avian orders
Evolutionary relationships among copies of feather beta (β) keratin genes from several avian orders
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DOI：
10.1093/icb/icn061
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发表时间：
2008-10-01
影响因子：
2.6
通讯作者：
Sawyer, Roger H.
中科院分区：
文献类型：
--
作者：
Glenn, Travis C.;French, Jeffrey O.;Sawyer, Roger H.
白色来航鸡（鸡形目，原鸡）的羽毛β（β）角蛋白是一个多基因家族的产物，该家族包括爪基因、羽毛基因、羽毛样基因和鳞片基因（Presland等人，1989 a）。在这里，我们的特点羽毛β-角蛋白基因在其他鸟类。我们使用鸡的序列设计了聚合酶链反应（PCR）引物，克隆得到的扩增子以分离单个拷贝，并对每个PCR反应的多个克隆进行测序，我们获得了预期大小的扩增子。来自8个鸟类目的18个物种的羽毛β-角蛋白表现出分类群内和分类群之间的DNA序列变异，甚至在基因的蛋白质编码区。这些数据的系统发育表明，在羽毛β-角蛋白基因复制开始于鹳形目（苍鹭、鹳和其盟友）、鹤形目（鹤、秧鸡和其盟友）和啄木鸟形目（啄木鸟和其盟友）之前，鸡形目（类似禽类的鸟类）、鹦鹉形目（鹦鹉），可能还有隼形目（猛禽）作为单独的谱系存在。来自Coraciiformes（翠鸟）和Columbiformes（鸽子）的单一物种的序列是单系的，并且具有显著的分歧，这表明这些鸟类中的羽毛β-角蛋白基因在这些物种最后与其他研究的类群共享共同祖先之后也发生了分歧。总体而言，这些数据表明，在鸟类相对近代的历史中，这种结构蛋白存在相当大的差异，并引发了有关鸟类和爬行动物的爪子、羽毛状和鳞片β-角蛋白的起源和同源性的问题。
The feather beta (beta) keratins of the white leghorn chicken (order Galliformes, Gallus gallus domesticus) are the products of a multigene family that includes claw, feather, feather-like, and scale genes (Presland et al. 1989a). Here we characterize the feather beta-keratin genes in additional bird species. We designed primers for polymerase chain reactions (PCR) using sequences available from chicken, cloned the resulting amplicons to isolate individual copies, and sequenced multiple clones from each PCR reaction for which we obtained amplicons of the expected size. Feather beta-keratins of 18 species from eight avian orders demonstrate DNA sequence variation within and among taxa, even in the protein-coding regions of the genes. Phylogenies of these data suggest that Galliformes (fowl-like birds), Psittaciformes (parrots), and possibly Falconiformes (birds of prey) existed as separate lineages before duplication of the feather beta-keratin gene began in Ciconiiformes (herons, storks, and allies), Gruiformes (cranes, rails, and allies), and Piciformes (woodpeckers and allies). Sequences from single species of Coraciiformes (kingfishers) and Columbiformes (pigeons) are monophyletic and strikingly divergent, suggesting feather beta-keratin genes in these birds also diverged after these species last shared a common ancestor with the other taxa investigated. Overall, these data demonstrate considerable variation in this structural protein in the relatively recent history of birds, and raise questions concerning the origin and homology of claw, feather-like, and scale beta-keratins of birds and the reptilian beta-keratins.