Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
Malar J. 2011 Sep 7;10:257. doi: 10.1186/1475-2875-10-257.
The reemergence of Plasmodium vivax in South Korea since 1993 represents a serious public health concern. Despite the importance in understanding genetic diversity for control strategies, however, studies remain inconclusive with the general premise that due to low rate of malaria transmission, there is generally low genetic diversity with very few strains involved. In this study, the genetic diversity and population structure of P. vivax in South Korea were explored by analysing microsatellite polymorphism.
Sequences for 13 microsatellite loci distributed across the twelve chromosomes of P. vivax were obtained from 58 South Korean isolates collected during two sampling periods, namely 1997-2000 and 2007. The sequences were used for the analysis of expected heterozygosity and multilocus genotype diversity. Population structure was evaluated using STRUCTURE version 2.3.2. Linkage disequilibrium was also analysed to investigate the extent of outbreeding in the P. vivax population.
Mean expected heterozygosity significantly increased from 0.382 in 1997-2000 to 0.545 in 2007 (P < 0.05). The number of multilocus genotypes was 7 and 27; and genotype diversity was statistically significant (P < 0.01) at 0.661 and 0.995 in 1997-2000 and 2007, respectively. Analysis by STRUCTURE showed a more complex population structure in 2007 than in 1997-2000. Linkage disequilibrium between 13 microsatellites, although significant in both time points, was notably lower in 2007.
The present microsatellite analysis clearly showed recent increase of genetic diversity and recent relaxation of the strong population structure observed in 1997-2000. These results suggest that multiple genotypes not present previously recently migrated into South Korea, accompanied by substantial outbreeding between different genotypes.
自 1993 年以来，间日疟原虫在韩国的重新出现引起了严重的公共卫生关注。然而，尽管了解遗传多样性对于控制策略很重要，但由于疟疾传播率低，一般认为遗传多样性通常较低，涉及的菌株很少，因此研究结果仍不确定。在这项研究中，通过分析微卫星多态性探索了韩国间日疟原虫的遗传多样性和种群结构。
从 1997-2000 年和 2007 年两次采样期间收集的 58 个韩国分离株中获得了分布在间日疟原虫 12 条染色体上的 13 个微卫星序列。使用这些序列分析了预期杂合度和多位点基因型多样性。使用 STRUCTURE 版本 2.3.2 评估了种群结构。还分析了连锁不平衡，以调查间日疟原虫种群中的异交程度。
平均预期杂合度从 1997-2000 年的 0.382 显著增加到 2007 年的 0.545（P < 0.05）。多态性基因型的数量为 7 和 27；基因型多样性在 1997-2000 年和 2007 年分别为 0.661 和 0.995，具有统计学意义（P < 0.01）。STRUCTURE 分析表明，2007 年的种群结构比 1997-2000 年更为复杂。虽然在两个时间点都存在显著的连锁不平衡，但在 2007 年显著降低。
本微卫星分析清楚地表明，遗传多样性最近有所增加，而 1997-2000 年观察到的种群结构明显放松。这些结果表明，以前不存在的多个基因型最近迁移到韩国，不同基因型之间发生了大量的异交。
