Multiple near-identical genotypes of Schistosoma japonicum can occur in snails and have implications for population-genetic analyses
Multiple near-identical genotypes of Schistosoma japonicum can occur in snails and have implications for population-genetic analyses
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DOI：
10.1016/j.ijpara.2008.05.015
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发表时间：
2008-12-01
影响因子：
4
通讯作者：
Blair, David
中科院分区：
文献类型：
--
作者：
Yin, Mingbo;Hu, Wei;Blair, David
我们的基因型（使用16或17个微卫星位点），许多成年日本血吸虫兔暴露于池尾蚴从少数自然感染的蜗牛在中国的几个地方。正如预期的那样，在这些蠕虫中发现重复的多位点基因型（MLG）。此外，发现了比用作尾蚴来源的蜗牛多得多的MLG，通常几乎相同。对这些结果的解释包括（i）基因分型错误，（ii）在每个感染的蜗牛内发展多个同胞毛蚴和（iii）体细胞突变，从单个毛蚴产生遗传上不同的尾蚴。为了控制基因分型错误，我们重新分析了许多个体蠕虫的样本，包括重复初始PCR。在一只蜗牛内产生多个兄弟姐妹毛蚴的说法不太可能是正确的，因为在主坐标分析中，几乎所有重复的MLG都属于同性簇。我们预期在多毛蚴感染中男女都有代表。此外，我们暴露了几个蜗牛感染一个单一的毛蚴。一只这样的蜗牛，通过实验感染的老鼠，产生了48只蠕虫。通过重新基因分型证实这些蠕虫中存在至少9个几乎相同的MLG。我们认为体细胞突变是我们结果最可能的解释。多个MLG对S. japonicum进行了讨论。(C)2008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。
We genotyped (using 16 or 17 microsatellite loci) numerous adult Schistosoma japonicum raised in rabbits exposed to pooled cercariae from small numbers of naturally infected snails from several localities in China. As expected, duplicate multi-locus genotypes (MLGs) were found among these worms. Additionally, many more MLGs, often near-identical, were found than snails used as sources of cercariae. Explanations for these results include (i) genotyping errors, (ii) development within each infected snail of multiple sibling miracidia and (iii) somatic mutation producing genetically varied cercariae from a single miracidium. To control for genotyping errors we re-analysed samples from many individual worms, including repeating the initial PCR. Explanations invoking the development of multiple sibling miracidia within a single snail are not likely to be correct because almost all duplicate MLGs fell within same-sex clusters in a principal coordinates analysis. We would expect both sexes to be represented in a multi-miracidium infection. In addition, we exposed several snails to infection by a single miracidium. One such snail, via an experimentally infected mouse, yielded 48 adult worms. The presence of at least nine near-identical MLGs among these worms was confirmed by re-genotyping. We regard somatic mutation as the most likely explanation for our results. The implications of multiple MLGs for population-genetic studies in S. japonicum are discussed. (C) 2008 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.