The mammalian αD-globin gene lineage and a new model for the molecular evolution of α-globin gene clusters at the stem of the mammalian radiation
The mammalian αD-globin gene lineage and a new model for the molecular evolution of α-globin gene clusters at the stem of the mammalian radiation
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DOI：
10.1016/j.ympev.2005.05.014
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发表时间：
2006-02-01
影响因子：
4.1
通讯作者：
Hope, RM
中科院分区：
文献类型：
--
作者：
Cooper, SJB;Wheeler, D;Hope, RM
我们通过哺乳动物α-珠蛋白基因的比较序列和系统发育分析探索了α-珠蛋白基因家族的进化。我们的分析揭示了哺乳动物中存在一种新的a-珠蛋白基因谱系，该谱系与鸟类、有鳞动物和海龟的α(D)-珠蛋白基因有关。该基因位于有袋动物、Sminthopsis macroura 和人类的 α-珠蛋白基因簇的中间。它存在于多种其他哺乳动物中，包括猪、牛、猫和狗，但在美洲有袋动物中是假基因。进化分析表明，该基因通常是在纯化选择下进化的，表明该基因具有功能。人类、猪和牛体内 mRNA 产物的存在也表明该基因已表达并且可能具有功能。这些分析支持这样的假设：α(D)-珠蛋白基因谱系具有古老的进化起源，早于羊膜动物的分化。有袋动物和人类的α珠蛋白基因簇的结构相似性表明，所有有袋动物和真兽类哺乳动物的共同祖先中存在8个基因簇（5'-xi 2-xi 1-alpha(D) -alpha 3-alpha 2-alpha 1-theta-omega-3'），其中包括7个α样基因和1个β样珠蛋白基因（omega-globin）。尽管欧米伽球蛋白已经从人类的α球蛋白基因簇中丢失，但这种基本结构在有袋动物和人类的谱系中保持相对稳定。 (c) 2005 Elsevier Inc. 保留所有权利。
We have explored the evolution of the alpha-globin gene family by comparative sequence and phylogenetic analyses of mammalian alpha-globin genes. Our analyses reveal the existence of a new a-globin gene lineage in mammals that is related to the alpha(D)-globin genes of birds, squamates and turtles. The gene is located in the middle of the alpha-globin gene cluster of a marsupial, Sminthopsis macroura and of humans. It exists in a wide variety of additional mammals, including pigs, cows, cats, and dogs, but is a pseudogene in American marsupials. Evolutionary analyses suggest that the gene has generally evolved under purifying selection, indicative of a functional gene. The presence of mRNA products in humans, pigs, and cows also suggest that the gene is expressed and likely to be functional. The analyses support the hypothesis that the alpha(D)-globin gene lineage has an ancient evolutionary origin that predates the divergence of amniotes. The structural similarity of alpha-globin gene clusters of marsupials and humans suggest that an eight gene cluster (5'-xi 2-xi 1-alpha(D) -alpha 3-alpha 2-alpha 1-theta-omega-3'), including seven alpha-like genes and one beta-like globin gene (omega-globin) existed in the common ancestor of all marsupial and eutherian mammals. This basic structure has remained relatively stable in marsupials and in the lineage leading to humans, although omega-globin has been lost from the alpha-globin gene cluster of humans. (c) 2005 Elsevier Inc. All rights reserved.