Joshi Hema
Malaria Research Centre (ICMR), 22 Sham Nath Marg, Delhi, India.
J Vector Borne Dis. 2003 Sep-Dec;40(3-4):78-83.
Present report deals with the genetic diversity existing among the field isolates of Plasmodium falciparum and P. vivax in India. Isoenzymes and molecular markers were used to analyse field isolates of P. falciparum and P. vivax. High level of length polymorphism was observed in repeat nucleotide sequences of MSP-1, MSP-2 and GLURP in P. falciparum isolates and CSP, GAM-1 and MSP-3 alpha in P. vivax isolates. In study populations a high proportion of isolates (up to 60%) were comprised of more than one genetically distinct parasite type--multiclonal. Presence of identical allelic forms of enzyme and DNA variations in different geographical areas and in different years suggest that isolates belong to a single random mating population of P. vivax and P. falciparum. Observed random combination of alleles in the field isolates suggest the unlinked nature of loci studied. Study supports the feasibility of using molecular markers for the identification of recrudescence in P. falciparum from fresh infection.
本报告探讨了印度恶性疟原虫和间日疟原虫野外分离株中存在的遗传多样性。采用同工酶和分子标记对恶性疟原虫和间日疟原虫的野外分离株进行分析。在恶性疟原虫分离株的MSP-1、MSP-2和GLURP以及间日疟原虫分离株的CSP、GAM-1和MSP-3α的重复核苷酸序列中观察到高度的长度多态性。在研究群体中,高比例的分离株(高达60%)由不止一种遗传上不同的寄生虫类型组成——多克隆。不同地理区域和不同年份中酶的相同等位基因形式和DNA变异的存在表明,这些分离株属于间日疟原虫和恶性疟原虫的单一随机交配群体。在野外分离株中观察到的等位基因随机组合表明所研究的基因座具有不连锁的性质。该研究支持使用分子标记来识别恶性疟原虫新鲜感染后的复发情况的可行性。