Infrequent genetic exchange and recombination in the mitochondrial genome of Candida albicans
Infrequent genetic exchange and recombination in the mitochondrial genome of Candida albicans
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DOI：
10.1128/jb.183.3.865-872.2001
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发表时间：
2001-02-01
影响因子：
3.2
通讯作者：
Kohn, LM
中科院分区：
文献类型：
--
作者：
Anderson, JB;Wickens, C;Kohn, LM
之前对二倍体核型的分析已经得出结论，白色念珠菌的种群中已经发生了重组。为了解决在有效的单倍体基因组中克隆和重组的可能性，我们对来自加拿大多伦多人类免疫缺陷病毒阳性患者的45株白色念珠菌和3株白色念珠菌的标准参考分离株、CA、CAI4和WO-1的线粒体DNA(MtDNA)的7个区域进行了测序。在7个区域的2,553个核苷酸中，62个多态核苷酸位点和7个INDELs在48个菌株中定义了9个不同的mtDNA单倍型。其中5个单倍型出现在一个以上的菌株中，表明mtDNA的克隆性增殖，对mtDNA单倍型的系统发育分析得到了一个最简约的树，该树中大多数发生平行变化的核苷酸位点聚集在与测序区域相对应的区块中。由于这些片段的存在，这种表观的同质性可以归因于个体之间不频繁的、过去的遗传交换和重组，而不是平行突变，在具有相同mtDNA单倍型的菌株之间，多位点核基因型比从核DNA的随机比较中预期的更相似。表明线粒体基因组的克隆性增殖伴随着核基因组的克隆性增殖。
Previous analyses of diploid nuclear genotypes have concluded that recombination has occurred in populations of the yeast Candida albicans, To address the possibilities of clonality and recombination in an effectively haploid genome, we sequenced seven regions of mitochondrial DNA (mtDNA) in 45 strains of C. albicans from human immunodeficiency virus-positive patients in Toronto, Canada, and 3 standard reference isolates of C. albicans, CA, CAI4, and WO-1. Among a total of 2,553 nucleotides in the seven regions, 62 polymorphic nucleotide sites and seven indels defined nine distinct mtDNA haplotypes among the 48 strains. Five of these haplotypes occurred in more than one strain, indicating clonal proliferation of mtDNA, Phylogenetic analysis of mtDNA haplotypes resulted in one most-parsimonious tree, Most of the nucleotide sites undergoing parallel change in this tree were clustered in blocks that corresponded to sequenced regions. Because of the existence of these blocks, the apparent homoplasy can be attributed to infrequent, past genetic exchange and recombination between individuals and cannot be attributed to parallel mutation, Among strains sharing the same mtDNA haplotypes, multilocus nuclear genotypes were more similar than expected from a random comparison of nuclear DNA. genotypes, suggesting that clonal proliferation of the mitochondrial genome was accompanied by clonal proliferation of the nuclear genome.