Studies on speciation and its origin of Schistosoma japonicum

日本血吸虫物种形成及其起源研究

基本信息

批准号：
10041188
负责人：
AGATSUMA Takeshi
金额：
$ 6.08万
依托单位：
Kochi Medical School (1999)Obihiro University of Agriculture and Veterinary Medicine (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

1. Nucleotide sequences of CO1, 28S and ITS2 were examined for samples from four species of the S.indicum group, Schistosoma indicum, S.spindale, S.nasale, S.incognitum collected from Bangladesh, Indonesia, Sri Lanka and Thailand, respecitively, and the NJ, UPGMA and Parsimony methods were used for phylogenetic analyses. The following results were obtained ; l)S.indicum and S.spindale were closely related to S.haematobium from Africa and to each other, while S.nasale has affinity with S.mansoni. 2) S.incognitum lies distant from the cluster that includes other three species of the S.indicum group and the African species. 2. A elephant schistosomes, Bivitellobilharzia nairi that belonged to the genus Schistosoma formerly, was found to show affinity to the Schistosoma species in a molecular level as well. 3. Nucleotide sequences of snail hosts in Sri Lanka and Bangladesh, I.exustus and Lymnaea spp., were also analyzed for the ITS2 and 28S regions, and found that I.exustus has a stronger affinity to Biomphalaria spp. than to Lymnaea spp. 4. Chromosomal analysis for the C-banding pattern showed that seven pairs of autosomes and sex chromosomes (Z and W) were species-specific, and large differences exist between Asian and African species of Schistosome. In particular, findings of AM inversion of chromosome 2 suggests that S.japonicum in Asia is of original type, while the African species, of derived type. 5. As a hypothesis, 1) Ancestral species of Schistosoma was diverged from Bivitellobilharzia nairi in Asia tens of millions years ago, and produced two species complex group, the S.sinensium and S.indicum group. 2) The S.japonicum group arose from ancestral species of the S.sinensium, adapting a new snail host, Oncomelania. 3) Ancestral species of the S.indicum group, adapting to a new snail host, Indoplanorbis, migrated into the African continent due to an unknown way, and gave rise to ancestral species of the African species.

1. 对分别采自孟加拉国、印度尼西亚、斯里兰卡和泰国的印度血吸虫组（Schistosoma indicum、S.spindale、S.nasale、S.incognitum）四个物种的样品进行了 CO1、28S 和 ITS2 的核苷酸序列检查。，并使用 NJ、UPGMA 和 Parsimony 方法进行系统发育分析。得到以下结果； l) S.indicum 和 S.spindale 与来自非洲的 S.haematobium 密切相关，并且彼此之间也密切相关，而 S.nasale 与 S.mansoni 有亲缘关系。 2) S.incognitum 与包括 S.indicum 组的其他三个物种和非洲物种的簇相距较远。 2. 一种大象血吸虫Bivitellobilharzia nairi，原属于血吸虫属，被发现在分子水平上也表现出与血吸虫物种的亲和力。 3.对斯里兰卡和孟加拉国蜗牛宿主I.exustus和Lymnaea spp.的ITS2和28S区域的核苷酸序列进行了分析，发现I.exustus对Biomphalaria spp.有更强的亲和力。比 Lymnaea spp。 4. C带型染色体分析表明，7对常染色体和性染色体（Z和W）具有种属特异性，亚洲和非洲血吸虫种之间存在较大差异。特别是，2号染色体AM倒位的结果表明亚洲的日本血吸虫是原始型，而非洲的日本血吸虫是衍生型。 5. 作为假设，1）血吸虫的祖先种在数千万年前从亚洲的 Bivitellobilharzia nairi 分化出来，产生了两个物种复合群，即 S.sinensium 和 S.indicum 群。 2）日本钉螺群起源于中华钉螺的祖先物种，适应了新的钉螺宿主——钉螺。 3) S.indicum群的祖先种，适应了新的蜗牛宿主Indoplanorbis，以未知的方式迁徙到非洲大陆，并产生了非洲种的祖先种。