It has been recognized as the most important model animal to analyze the origin and evolution of vertebrates . study on the gene structure , function and expression in amphioxus will greatly contribute to the origin and evolution of the vertebrates 利用分子生物学手段，研究文昌鱼有关基因的结构、进化和表达，可为我们从分子水平上解开脊椎动物起源的奥秘；更重要的是，将进化与发育联系起来，可以更清楚地揭示有关基因在发育中的作用。
However , only three species of the cephalochordate including b . lanceolatum , b . floridae , and b . belcheri , have so far been studied for their chromosome numbers , and the karyotypic analysis and banding study of amphioxus chromosomes remains largely untouched Floridae 、 b belcheri三种文昌鱼染色体数目。有关文昌鱼染色体核型和带型的研究尚未见任何报道，文昌鱼染色体核型和带型的研究将为比较基因组学和细胞遗传学研究提供珍贵的背景资料。
Amphioxus , an existing animal that belongs to the phylum chordata , subphyla cephalochordata , is always regarded as the invertebrates which is the nearest to the vertebrates . it has great sense on the research of how the vertebrates develop from invertebrates 长久以来，文昌鱼一直被认为是现存的与脊椎动物亲缘关系最近的无脊椎动物( stokeandholland , 1998 ; zhangetal . , 2001 ) ，在脊椎动物如何由无脊椎动物进化而来这一著名的生物学难题中占据重要的位置。
As the number of r - bands is associated with that of genes , and most genes that have been mapped to mammalian chromosomes with sufficient precision are usually distributed in r - bands rather than in g - bands . this is apparently in agreement with the hypothesis of two rounds of extensive gene duplication leading to the origin of the vertebrates R带的数目与基因的多少相关，许多哺乳动物的基因已精确地进行了染色体定位，大量报道证明它们一般分布在r带上，而不是g带上，文昌鱼r带的数目恰恰与脊椎动物起源时发生了两次基因倍增的假设相吻合。
The hemagglutinating activity of amphioxus skin mucus was decreased after heating at 60 for 30 min , and was almost lost upon heating at 100 for 30 min . the hemagglutinating activity of the skin mucus remained stable in the ph range from 6 to 10 , but it was inactivated at ph above 10 or below 6 . the hemagglutinating activity in the skin mucus is inhibited by d - galactose , which is same with the hemagglut inating activity of the humoral fluids of amphioxus 在60保温30分钟后，凝集素的凝集活性下降，在100保温30分钟后，凝集素凝集活性几乎完全消失；在ph6 - 10的范围内，凝集素的凝集活性稳定， ph大于10小于6的条件下，凝集素的凝集活性消失；文昌鱼体表粘液中的凝集素受d -半乳糖苷的抑制。
Phylogenetic analysis based on the amino acids of the ubiquitin / ribosomal fused proteins of different animals well reflected the established phylogeny of the chosen organisms , and amphioxus was branched off from chordates and formed a separate cluster with an intermediate placement between invertebrates and vertebrates in the tree 通过对ubiquitin的系统进化分析，发现文昌鱼ubf80除了具有脊椎动物和无脊椎动物的特征外，还具有自己的一些独特的特征，从分子水平上支持了文昌鱼是脊索动物进化过程中的一侧枝的观点。
In this paper , the presence of lectins in the skin mucus of amphioxus was verified by the aggutination assay and the effects of physical and chemical treatments on hemagglutination activity of amphioxus skin mucus were tested by the means of heat treatment and ph treatment 本文利用青岛文昌鱼体表粘液凝集反应、热处理、 ph处理文昌鱼体表粘液及糖抑制文昌鱼体表粘液凝集反应等免疫学实验方法验证了青岛文昌鱼(且belcheritsingtaunese )体表粘液中的凝集素的存在并对其性质进行了研究。
Considering of the specificity of the degenerative primer designed in this pcr reaction , the identity between the sequence we wanted and the fragment of pcr product and the presence of asmaspa , asmaspb , clr and cls ( the homologous gene of masp gene ) in halocynthia roretzi , a japanese ascidian , we believe that the sequence of pcr product is some part of the masp gene or masp homologous gene 基于本实验中所设计的引物为特异性简并引物，测序基因通过比较得到与预期片段有一定的同源性以及masp同源物asmaspa 、 asmaspb 、 clr和cls在海鞘中存在的事实，我们可以初步推测，本实验pcr反应所克隆的片段可能为文昌鱼masp或其同源基因的一部分序列。
The presence of complement - like activity in the humoral fluid of amphioxus was examined . the complement classical pathway ( cp ) activity is assayed by determining the amount of serum required to hemolyse a given number of sensitized sheep red blood cells ( srbc ) , whereas the complement alternative pathway ( ap ) activity measured in the same manner , but by using rabbit red blood cells ( rarbc ) instead of sensitized srbc 文昌鱼体液可溶解悬浮在10mmol legta - mg - gvb缓冲液中的正常的兔血红细胞、绵羊红细胞、及部分哺乳动物、鸟类、两栖类和鱼类的代表动物的血红细胞；而在gvb ~ ( 2 + )缓冲液中时对抗体包被的绵羊红细胞却没有溶血活性。
G - banding the gtg banding ( g - banding ) was carried out by the standard trypsin method with slight modification , which works well for protochordate because a good number of reproducible g - bands are consistently obtained from the embryonic cells of late blastulae and early gastrulae of amphioxus b . belcheri tsingtauense G带型用稍作修改的标准的胰酶显带技术，进行gtg带纹的显示，它们能较好地显示头索动物青岛文昌鱼的晚期囊胚和早期原肠胚的中期染色体的g带，并且重复性好。
