Adaptive evolution of Toll-like receptor 5 in domesticated mammals.
Adaptive evolution of Toll-like receptor 5 in domesticated mammals.
复制标题
DOI：
10.1186/1471-2148-12-122
复制
发表时间：
2012-07-24
影响因子：
3.4
通讯作者：
Emes RD
中科院分区：
文献类型：
--
作者：
Smith SA;Jann OC;Haig D;Russell GC;Werling D;Glass EJ;Emes RD
以往的研究认为，哺乳动物的Toll样受体（TLR）由于其在病原体检测中的作用，在多样化选择下进化。为了确定是否是这种情况，我们研究了TLR5基因在哺乳动物的个体物种和定义的分支中的适应性进化程度。为了支持以前的研究，我们发现了哺乳动物TLR5适应性进化的证据。然而，我们也表明，TLR5基因的家畜有一个浓度的单核苷酸多态性，这表明一个特定的适应签名。使用密码子模型的演变，我们已经确定了浓度的快速演变的密码子内TLR5细胞外结构域的主机和细菌表面蛋白鞭毛蛋白之间的相互作用的网站。结果表明，病原体和宿主之间的相互作用可能是通过物种间的竞争驱动TLR5的适应性变化。为了支持这一点，我们已经确定了单核苷酸多态性（SNP）的羊和牛TLR5基因是共定位和一致的预测适应性密码子，这表明在该地区的TLR5基因的适应是正在进行的国内物种。
Previous studies have proposed that mammalian toll like receptors (TLRs) have evolved under diversifying selection due to their role in pathogen detection. To determine if this is the case, we examined the extent of adaptive evolution in the TLR5 gene in both individual species and defined clades of the mammalia. In support of previous studies, we find evidence of adaptive evolution of mammalian TLR5. However, we also show that TLR5 genes of domestic livestock have a concentration of single nucleotide polymorphisms suggesting a specific signature of adaptation. Using codon models of evolution we have identified a concentration of rapidly evolving codons within the TLR5 extracellular domain a site of interaction between host and the bacterial surface protein flagellin. The results suggest that interactions between pathogen and host may be driving adaptive change in TLR5 by competition between species. In support of this, we have identified single nucleotide polymorphisms (SNP) in sheep and cattle TLR5 genes that are co-localised and co-incident with the predicted adaptive codons suggesting that adaptation in this region of the TLR5 gene is on-going in domestic species.