Contrasting genetic structure in Plasmodium vivax populations from Asia and south America
Contrasting genetic structure in Plasmodium vivax populations from Asia and south America
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DOI：
10.1016/j.ijpara.2007.02.010
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发表时间：
2007-07-01
影响因子：
4
通讯作者：
Anderson, Tim J. C.
中科院分区：
文献类型：
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作者：
Imwong, Mallika;Nair, Shalim;Anderson, Tim J. C.
恶性疟原虫种群在连锁不平衡、种群分化和多样性等方面存在显著差异，但间日疟原虫的遗传结构研究却很不完整。我们从三个亚洲国家和哥伦比亚的五个地点收集了345例间日疟原虫感染，对9个带有2-8 bp基序的串联重复基因座进行了基因分型。我们观察到9-37个等位基因每个位点和高多样性（H-e = 0.72-0.79，平均值= 0.75）在所有国家。多重克隆感染的数量差异很大：这些在哥伦比亚和印度很少见，但在泰国和老挝，>60%的分离株在至少一个位点携带多个等位基因。然而，在许多样本中，9个基因座中只有1个或2个显示>1个等位基因，表明感染内的突变可能导致高估真实的多重携带率。在哥伦比亚人群中经常发现相同的9个位点的基因型，导致强烈的连锁不平衡。这些相同的基因型在时间上强烈聚集，与克隆的流行性传播和随后的等位基因关联的破裂一致，表明在这个国家近亲繁殖的高比率和低有效重组率。与此相反，相同的基因型是罕见的，位点随机关联在所有三个亚洲人群，符合较高的异交和重组率。我们观察到不同亚洲国家之间的差异较低但显著（标准化，F-ST =0.13-0.45）。相比之下，我们看到哥伦比亚境内采集地点之间的差异更大（标准化F-ST = 0.4-0.7），各大洲之间的差异也很大（标准化F-ST = 0.48-0.79）。观察到的异质性多克隆携带率，连锁不平衡和人口分化是类似的，在某些方面，但不是所有的恶性疟原虫中观察到的，并有重要的意义关联作图研究的设计，并解释间日疟原虫流行病学。(C)2007年澳大利亚寄生虫学会由爱思唯尔有限公司出版。保留所有权利。
Populations of Plasmodium falciparum show striking differences in linkage disequilibrium, population differentiation and diversity, but only fragmentary data exists on the genetic structure of Plasmodium vivax. We genotyped nine tandem repeat loci bearing 2-8 bp motifs from 345 P. vivax infections collected from three Asian countries and from five locations in Colombia. We observed 9-37 alleles per locus and high diversity (H-e = 0.72-0.79, mean = 0.75) in all countries. Numbers of multiple clone infections varied considerably: these were rare in Colombia and India, but >60% of isolates carried multiple alleles in at least one locus in Thailand and Laos. However, only one or two of the nine loci show >1 allele in many samples, suggesting that mutation within infections may result in overestimation of true multiple carriage rates. Identical nine-locus genotypes were frequently found in Colombian populations, contributing to strong linkage disequilibrium. These identical genotypes were strongly clustered in time, consistent with epidemic transmission of clones and subsequent breakdown of allelic associations, suggesting high rates of inbreeding and low effective recombination rates in this country. In contrast, identical genotypes were rare and loci were randomly associated in all three Asian populations, consistent with higher rates of outcrossing and recombination. We observed low but significant differentiation between different Asian countries (standardized, F-ST =0.13-0.45). In comparison, we see greater differentiation between collection locations within Colombia (standardized F-ST = 0.4-0.7), and strong differentiation between continents (standardized F-ST = 0.48-0.79). The observed heterogeneity in multiple clone carriage rates, linkage disequilibrium and population differentiation are similar in some, but not all, respects to those observed in P. falciparum, and have important implications for the design of association mapping studies, and interpretation of P. vivax epidemiology. (C) 2007 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.