Long-term genetic stability and population dynamics of laboratory strains of Schistosoma mansoni.
Long-term genetic stability and population dynamics of laboratory strains of Schistosoma mansoni.
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DOI：
10.1645/ge-2463.1
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发表时间：
2010-10
期刊：
影响因子：
--
通讯作者：
Blanton RE
中科院分区：
文献类型：
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作者：
Blank WA;Test MR;Liu SF;Lewis FA;Blanton RE
Measures of genetic differentiation between populations are a useful tool for understanding the long-term dynamics of parasite communities. We followed the allele frequencies of microsatellite markers in samples taken over a period of 16 years from the CWRU laboratory strain of Schistosoma mansoni. DNA was isolated from 46 pooled or aggregated samples of adults, eggs, and cercariae and was genotyped for 14 tri- or tetranucleotide microsatellite markers. Two S. mansoni reference strains, including the strain from which the CWRU line was originally derived, were also analyzed over shorter periods of time. We observed that the long-term allele frequencies are generally stable in large populations of this parasite that utilizes both sexual and asexual reproduction. The CWRU strain, however, showed 2 periods of marked deviations from stability. These corresponded with a period of admixture from one of the reference strains and a period of genetic drift when the population size was greatly reduced. Using genetic differentiation measures we demonstrate which of the reference strains was the source of the admixture. The 2 populations show little differentiation at the point of mixture, and a new equilibrium is reached as the “migrants” become blended into the existing CWRU population. This new equilibrium was consistent with 30% admixture from the reference strain. We also observed that the allele frequencies of the different developmental stages were essentially identical. Accounting only for the intensity or prevalence of parasite populations may fail to register significant changes in population structure that could have implications for resistance, morbidity and the design of control measures.
