Molecular Evolution of Growth Hormone and Classification of Fishes

该项目的目标是在序列比较的基础上构建生长激素和催乳素家族的分子系统发育树，并使用氨基酸变化比率半定量动物的系统发育距离。虽然现在有大量的结构信息的生长激素和催乳素，它仍然是有限的哺乳动物和硬骨鱼类物种。我们从哺乳动物的关键物种中分离出了生长激素和催乳素，并测定了爬行动物（鳄鱼和海龟）、两栖动物（牛蛙）的生长激素的氨基酸序列。原始硬骨鱼（鲟鱼）、硬骨鱼（大西洋鳕鱼、鲶鱼、比目鱼）、板鳃类（大青鲨）;哺乳动物（大须鲸和抹香鲸）、爬行动物（短吻鳄、鳄鱼、海龟）、两栖动物（牛蛙）、原始硬骨鱼（肺鱼）、硬骨鱼（鲶鱼和比目鱼）的催乳素。在调查过程中，我们发现了一种新的垂体瘤 ...更多信息 从硬骨鱼类中提取的蛋白质，如大西洋鳕鱼、比目鱼和鲑鱼。完整氨基酸序列的解析显示，这些蛋白质与生长激素和催乳素有着遥远而相似的关系。因此，这种蛋白质是生长激素催乳素家族的一个新成员，被命名为“生长抑素”。用Fitch和Margoliash的方法构建了四足类和硬骨鱼类的生长激素分子系统树。硬骨鱼的躯干比四足动物的躯干大得多，表明四足动物的生长激素在分子进化过程中具有更大的保守性。突变的程度与遗传学一致。因此，这些物种的系统发育距离可以通过每100个残基的氨基酸变化来半定量。生长激素、催乳素和生长激素肌动蛋白的进化关系也通过序列比较进行了估计。估计表明，这些垂体激素从一个共同的祖先基因复制。少

The goal of the project is to construct a molecular phylogenetic tree of the growth hormone and prolactin family on the basis of sequence comparisons and to semi-quantify the phylogenetic distance of animals using ratios of amino acid changes. Although a substantial amount of structural information is now available on growth hormones and prolactins, it is still limited to mammalian and teleostean species. We have isolated growth hormones and prolactins from the species which are key-species in phylogeny and determined the complete amino acid sequences of the followings ; growth hormones from reptiles (crocodile and sea turtle), amphibian (bullfrog). Primitive bony fish (sturgeon), teleosts (Atlantic cod, catfish, flounder), elasmobranch (blue shark) ; prolactin from mammals (sei and sperm whale), reptiles (alligator, crocodile, sea turtle), amphibian (bullfrog), primitive bony fish (lungfish), teleosts (catfish and flounder). In the course of this investigation, we found a novel pituit … More ary protein from teleost species, such as Atlantic cod, flounder, and chum salmon. Elucidation of the complete amino acid sequences revealed that the proteins are distantly and similarly related to grow hormone and prolactin. Consequently, the protein, which is a new member of the growth hormone prolactin family, was named "somatolactin". A molecular phylogenetic tree of growth hormones which was constructed by the method of Fitch and Margoliash consists of two trunks, tetrapods and teleosts. The teleost trunk is much bigger than the tetrapod trunk, indicating the greater conservation of tetrapod growth hormones during molecular evolution. The degree of mutational changes is in good conformity with phylogeny. Therefore, phylogenetic distances of these species could be semi-quantified by amino acid changes per 100 residues. Evolutionary relationship of growth hormone, prolactin and somatolactin was also estimated by sequence comparison. The estimation suggests that these pituitary hormones diverged from a common ancestor by gene duplication. Less