Rogers W O, Wirth D F
Proc Natl Acad Sci U S A. 1987 Jan;84(2):565-9. doi: 10.1073/pnas.84.2.565.
Previous work has shown that the kinetoplast minicircle DNA of Leishmania species exhibits species-specific sequence divergence and this observation has led to the development of a DNA probe-based diagnostic test for leishmaniasis. In the work reported here, we demonstrate that the minicircle is composed of three types of DNA sequences with differing specificities reflecting different rates of DNA sequence change. A library of cloned fragments of kinetoplast DNA (kDNA) from Leishmania mexicana amazonensis was prepared and the cloned subfragments were found to contain DNA sequences with different taxonomic specificities based on hybridization analysis with various species of Leishmania. Four groups of subfragments were found, those that hybridized with a large number of Leishmania sp. as well as sequences unique to the species, subspecies, or isolate. Analysis of nested deletions of a single, full-length minicircle demonstrates that these different taxonomic specificities are contained within a single minicircle. This implies that different regions of a single minicircle have DNA sequences that diverge at different rates. These sequences represent potentially valuable tools in diagnostic, epidemiologic, and ecological studies of leishmaniasis and provide the basis for a model of kDNA sequence evolution.
先前的研究表明，利什曼原虫属的动基体小环DNA呈现出物种特异性的序列差异，这一发现促使人们开发出一种基于DNA探针的利什曼病诊断测试。在本文报道的研究中，我们证明小环由三种具有不同特异性的DNA序列组成，这些特异性反映了不同的DNA序列变化速率。制备了来自亚马逊利什曼原虫的动基体DNA（kDNA）克隆片段文库，并通过与各种利什曼原虫物种的杂交分析发现，克隆的亚片段包含具有不同分类特异性的DNA序列。发现了四组亚片段，即那些与大量利什曼原虫物种杂交的片段以及该物种、亚种或分离株特有的序列。对单个全长小环的嵌套缺失分析表明，这些不同的分类特异性包含在单个小环内。这意味着单个小环的不同区域具有以不同速率发生分歧的DNA序列。这些序列是利什曼病诊断、流行病学和生态学研究中潜在的有价值工具，并为kDNA序列进化模型提供了基础。
