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。检查了Co1，28S和ITS2的核苷酸序列，以从孟加拉国，印度尼西亚，Sri Lanka和Thailand和Thailand和Thailand和Thailand和Thailand和NJ，NJ，upgma和Parsimys Sartimenty Sartims的四种样本，S.indicum群，Scistosoma Inminum，S.Spindale，S.nasale，S.incognitum，S.incognitum进行了样品。获得以下结果； l）Indicum和S.spindale与来自非洲的s.haematobium以及彼此之间密切相关，而S.nasale与S.Mansoni具有亲和力。 2）incmognitum在远离群集中，其中包括其他三种s.indicum群和非洲物种。 2。属于以前属于该血吸虫属的大象血吸虫，属于属于该血吸虫属的Bivitellobilharzia Nairi，也显示出与分子水平的血吸虫物种的亲和力。 3。在斯里兰卡和孟加拉国，i.exustus和lymnaea spp。的蜗牛宿主的核苷酸序列也被分析了ITS2和28S区域，发现i.exustus与生物脑属于生物脑的亲和力更强。比lymnaea spp。 4。对C带模式的染色体分析表明，七对常染色体和性别染色体（Z和W）是物种特异性的，并且在亚洲和非洲的Schistosom物种之间存在很大差异。特别是，染色体2反转的AM反转发现表明，亚洲的japonicum是原始类型的，而非洲物种是衍生类型的。 5。作为一个假设，1）在亚洲的Bivitellobilharzia nairi中，祖先种群在亚洲数百万年前分歧，并产生了两个物种复合物组，即S. sinensium and s.indicum群。 2）japonicum群来自s. sinemensium的祖先物种，适应新的蜗牛宿主，oncomelania。 3）S.Indicum群体的祖先物种适应新的蜗牛宿主Indoplanorbis，由于未知的方式迁移到非洲大陆，并引起了非洲物种的祖先物种。