Population genetics provides evidence for recombination in Giardia
Population genetics provides evidence for recombination in Giardia
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DOI：
10.1016/j.cub.2007.10.020
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发表时间：
2007-11-20
期刊：
影响因子：
9.2
通讯作者：
Sterling, Charles R.
中科院分区：
文献类型：
--
作者：
Cooper, Margarethe A.;Adam, Rodney D.;Sterling, Charles R.
兰伯氏贾第虫(syn。肠贾第虫，十二指肠贾第虫是一种具有两个核的肠道原生动物寄生虫，可能是最早的分支真核生物之一。然而，至少某些特征的基本形式的发现，如高尔基体和线粒体，驳斥了它从真核谱系出现于某些真核特征发展之前的提议。最近对基因组中许多已知的柔化所需基因的认识也对贾第鞭毛虫最初是无性生殖的观点产生了怀疑，但到目前为止还没有直接证据表明贾第鞭毛虫有性生殖，种群数据表明无性生殖。我们对来自秘鲁高流行地区的A2基因型参考菌株JH和5株A2基因型分离株进行了多位点序列评估。来自不同染色体的基因座产生了显著不同的系统发育树，表明它们不具有相同的进化史；在单个基因座内，重组测试为减数分裂重组提供了显著的统计支持。这些观察结果提供了支持贾第鞭毛虫有性繁殖的遗传数据。
Giardia lamblia(syn. Giardia intestinalis, Giardia duodenalis) is an enteric protozoan parasite with two nuclei, and it might be one of the earliest branching eukaryotes [1]. However, the discovery of at least rudimentary forms of certain features, such as Golgi and mitochondria, has refuted the proposal that its emergence from the eukaryotic lineage predated the development of certain eukaryotic features. The recent recognition of many of the genes known to be required for melosis in the genome has also cast doubt on the idea that Giardia is primitively asexual, but so far there has been no direct evidence of sexual reproduction in Giardia, and population data have suggested clonal reproduction. We did a multilocus sequence evaluation of the genotype A2 reference strain, JH, and five genotype A2 isolates from a highly endemic area in Peru. Loci from different chromosomes yielded significantly different phylogenetic trees, indicating that they do not share the same evolutionary history; within individual loci, tests for recombination yielded significant statistical support for meiotic recombination. These observations provide genetic data supportive of sexual reproduction in Giardia.