Agatsuma T, Iwagami M, Liu C X, Rajapakse R P V J, Mondal M M H, Kitikoon V, Ambu S, Agatsuma Y, Blair D, Higuchi T
Department of Environmental Health Science, Kochi Medical School, Oko, Nankoku, Japan.
J Helminthol. 2002 Mar;76(1):7-19. doi: 10.1079/joh200191.
Schistosoma species have traditionally been arranged in groups based on egg morphology, geographical origins, and the genus or family of snail intermediate host. One of these groups is the 'S. indicum group' comprising species from Asia that use pulmonate snails as intermediate hosts. DNA sequences were obtained from the four members of this group (S. indicum, S. spindale, S. nasale and S. incognitum) to provide information concerning their phylogenetic relationships with other Asian and African species and species groups. The sequences came from the second internal transcribed spacer (ITS2) of the ribosomal gene repeat, part of the 28S ribosomal RNA gene (28S), and part of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene. Tree analyses using both distance and parsimony methods showed the S. indicum group not to be monophyletic. Schistosoma indicum, S. spindale and S. nasale were clustered among African schistosomes, while S. incognitum was placed as sister to the African species (using ITS2 and 28S nucleotide sequences and CO1 amino acid sequences), or as sister to all other species of Schistosoma (CO1 nucleotide sequences). Based on the present molecular data, a scenario for the evolution of the S. indicum group is discussed.
血吸虫种类传统上是根据虫卵形态、地理起源以及中间宿主蜗牛的属或科来进行分组的。其中一组是“印度血吸虫组”，包括来自亚洲的以肺螺类蜗牛作为中间宿主的血吸虫种类。从该组的四个成员（印度血吸虫、间插血吸虫、鼻血吸虫和隐匿血吸虫）获取了DNA序列，以提供有关它们与其他亚洲和非洲种类及种类组之间系统发育关系的信息。这些序列来自核糖体基因重复序列的第二内部转录间隔区（ITS2）、28S核糖体RNA基因（28S）的一部分以及线粒体细胞色素c氧化酶亚基1（CO1）基因的一部分。使用距离法和简约法进行的系统树分析表明，印度血吸虫组并非单系类群。印度血吸虫、间插血吸虫和鼻血吸虫聚集在非洲血吸虫之中，而隐匿血吸虫则被定位为非洲种类的姐妹种（使用ITS2和28S核苷酸序列以及CO1氨基酸序列），或者是所有其他血吸虫种类的姐妹种（CO1核苷酸序列）。基于目前的分子数据，讨论了印度血吸虫组的进化情况。
