Kelly J M, Law J M, Chapman C J, Van Eys G J, Evans D A
Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, U.K.
Mol Biochem Parasitol. 1991 Jun;46(2):253-63. doi: 10.1016/0166-6851(91)90049-c.
In the genus Leishmania there has been no convincing demonstration of genetic exchange, and it has been proposed that reproduction is clonal. However, preliminary characterization of two strains of Leishmania isolated from wild animals in a zoonotic focus of cutaneous leishmaniasis in the Eastern Province of Saudi Arabia, has suggested that they may represent hybrids of Leishmania major and Leishmania arabica. Evidence presented here strongly supports this hypothesis. Isoenzyme analysis and molecular karyotyping of cloned organisms indicated that the putative hybrids are distinct from other species of Leishmania, and possess characteristics of both L. major and L. arabica. Experiments using highly specific probes demonstrated that kinetoplast minicircle DNA from the putative hybrid contained L. major-specific, but not L. arabica-specific sequences. DNA fingerprinting data obtained using 6 genomic DNA probes were consistent in all cases with a L. major/L. arabica recombinant genotype, and implied both diploidy and allelic segregation. These observations suggest that sexual reproduction may generate genetic diversity within natural Leishmania populations.
在利什曼原虫属中，尚未有令人信服的基因交换证据，因此有人提出其繁殖方式为克隆繁殖。然而，对从沙特阿拉伯东部省一个皮肤利什曼病动物源地的野生动物中分离出的两株利什曼原虫进行的初步鉴定表明，它们可能是硕大利什曼原虫和阿拉伯利什曼原虫的杂交种。本文提供的证据有力地支持了这一假说。对克隆生物体的同工酶分析和分子核型分析表明，假定的杂交种与利什曼原虫的其他物种不同，具有硕大利什曼原虫和阿拉伯利什曼原虫的特征。使用高度特异性探针进行的实验表明，假定杂交种的动基体小环DNA含有硕大利什曼原虫特异性序列，但不含有阿拉伯利什曼原虫特异性序列。使用6种基因组DNA探针获得的DNA指纹数据在所有情况下均与硕大利什曼原虫/阿拉伯利什曼原虫重组基因型一致，并暗示了二倍体和等位基因分离。这些观察结果表明，有性繁殖可能在自然利什曼原虫种群中产生遗传多样性。
