Escalante A A, Grebert H M, Chaiyaroj S C, Magris M, Biswas S, Nahlen B L, Lal A A
Instituto Venezolano de Investigaciones Científicas, Apartado 21827, 1020-A, Caracas, Venezuela.
Mol Biochem Parasitol. 2001 Apr 6;113(2):279-87. doi: 10.1016/s0166-6851(01)00229-8.
We have investigated the genetic diversity of the gene encoding the apical membrane antigen-1 (AMA-1) in natural populations of Plasmodium falciparum from western Kenya and compared it with parasite populations from other geographic regions. A total of 28 complete sequences from Kenya, Thailand, India, and Venezuela field isolates were obtained. The genetic polymorphism is not evenly distributed across the gene, which is in agreement with the pattern reported in earlier studies. The alleles from Kenya exhibit 20 and 30% more polymorphism than that found in Southeast Asia and Venezuelan alleles, respectively. Based on the gene genealogies derived from sequencing data, no evidence for allele families was found. We have found evidence supporting limited gene flow between the parasite populations, specifically, between the Southeast Asian and Venezuelan isolates; however, no alleles could be linked to a specific geographic region. This study reveals that positive natural selection is an important factor in the maintenance of genetic diversity for AMA-1. We did not find conclusive evidence indicating intragenic recombination is important in the generation of the AMA-1 allelic diversity. The study provides information on the genetic diversity of the AMA-1 gene that would be useful in vaccine development and testing, as well as in assessing factors that are involved in the generation and maintenance of the genetic diversity in P. falciparum.
我们研究了肯尼亚西部恶性疟原虫自然种群中编码顶端膜抗原-1（AMA-1）的基因的遗传多样性，并将其与其他地理区域的疟原虫种群进行了比较。从肯尼亚、泰国、印度和委内瑞拉的野外分离株中总共获得了28个完整序列。遗传多态性在整个基因中分布不均，这与早期研究报道的模式一致。来自肯尼亚的等位基因分别比东南亚和委内瑞拉等位基因的多态性高20%和30%。基于测序数据得出的基因谱系，未发现等位基因家族的证据。我们发现有证据支持疟原虫种群之间存在有限的基因流动，特别是东南亚和委内瑞拉分离株之间；然而，没有等位基因可以与特定地理区域相关联。这项研究表明，正向自然选择是维持AMA-1遗传多样性的重要因素。我们没有找到确凿证据表明基因内重组在AMA-1等位基因多样性的产生中起重要作用。该研究提供了有关AMA-1基因遗传多样性的信息，这将有助于疫苗开发和测试，以及评估参与恶性疟原虫遗传多样性产生和维持的因素。
