The use of DNA hybridization and numerical taxonomy in determining relationships between Trypanosoma brucei stocks and subspecies
The use of DNA hybridization and numerical taxonomy in determining relationships between Trypanosoma brucei stocks and subspecies
复制标题
利用 DNA 杂交和数值分类学确定布氏锥虫种群和亚种之间的关系
作者：
P. Paindavoine;E. Pays;M. Laurent;Y. Geltmeyer;D. L. Ray;D. Mehlitz;M. Steinert
本研究对来自非洲不同国家的71个布氏锥虫亚种和1个布氏锥虫亚种的细胞核DNA进行了分析。evansi股票，已经分析了限制性内切酶消化，凝胶电泳和分子杂交与锥虫表面抗原特异性和未定义的基因组DNA探针的组合使用。与T. brucei brucei和T. brucei rhodesiense股票，所有T. B.冈比亚种的特征在于保守的、特异的DNA带型，与探针无关。这使得T. B. gambiense将被明确识别。相反，T. B. brucei和T. B.不能用相同的标准区分的Rhodesiense，两者都产生高度可变的DNA带型。我们的数据证实，家畜如猪、狗和羊构成了T。B.冈比亚的。使用的DNA杂交模式的数值分析，我们已经测量了72锥虫股票之间的相似程度。研究表明，T. B.冈比亚种群属于同一个同质种群，而另外两个亚种的种群似乎分布在几个异质群体中，其中一些群体与锥虫的地理来源有关。结果表明：（i）T. B. gambiense作为一个真实的亚种，相对于"non-gambiense"组经历了明显的进化，（ii）所谓的T. B. rhodesiense亚种不适合任何组证明了我们的支序分析，因此不出现作为一个独特的亚种和（iii）'非冈比亚'锥虫可能比T。B.冈比亚的。不同方面的锥虫的关系和进化进行了讨论。
SUMMARY The nuclear DNAs of 71 trypanosome stocks from different African countries, representative of the three Trypanosoma brucei subspecies, and one T. evansi stock, have been analysed by the combined use of restriction endonuclease digestion, gel electrophoresis and molecular hybridization with both trypanosome surface-antigen-specific and undefined genomic DNA probes. In contrast with T. brucei brucei and T. brucei rhodesiense stocks, all the T. b. gambiense stocks are characterized by a conserved, specific DNA band pattern, regardless of the probe. This allows T. b. gambiense to be non-ambiguously identified. On the contrary, T. b. brucei and T. b. rhodesiense, which could not be discriminated by the same criteria, both yield highly variable DNA band patterns. Our data confirm that domestic animals like pig, dog and sheep constitute a potential reservoir for T. b. gambiense. Using a numerical analysis of the DNA hybridization patterns we have measured the degree of similarity between the 72 trypanosome stocks. This investigation shows that all T. b. gambiense stocks are included in the same homogeneous population, while the stocks from the two other subspecies seem to be distributed in several heterogeneous groups, some of these showing correlation with the geographical origin of the trypanosomes. It is concluded that (i) T. b. gambiense stands out as a real subspecies that has undergone a distinct evolution relative to the ‘non-gambiense’ group, (ii) the alleged T. b. rhodesiense subspecies does not fit with any of the groups evidenced by our cladistic analysis and hence does not appear as a distinct subspecies and (iii) ‘non-gambiense’ trypanosomes are probably evolving much more rapidly than T. b. gambiense. Different aspects of trypanosome relationships and evolution are discussed.