Wielinga C M, Thompson R C A
WHO Collaborating Centre for the Molecular Epidemiology of Parasitic Infections, School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Murdoch, Western Australia 6150, Australia.
Parasitology. 2007 Nov;134(Pt 12):1795-821. doi: 10.1017/S0031182007003071. Epub 2007 Jun 19.
A review of the Giardia duodenalis sequences currently available on the GenBank database was completed to compare the different genotyping loci (small subunit ribosomal DNA, glutamate dehydrogenase, triose-phosphate isomerase and beta giardin) for their ability to discern assemblage and subassemblage groups and infer phylogenetic relationships. In total, 405 Giardia duodenalis sequences were sorted and aligned to examine the substitutions within and between the assemblages - A and B (zoonotic), C and D (dogs), E (livestock), F (cats) and G (rodents). It was found that all of the genes could reproducibly group isolates into their assemblages and that the AI/AII subassemblage groups were robust and identifiable at all loci. However, the assemblage B subgroups were not reproducible at half of the loci (small subunit ribosomal DNA and beta giardin), not due to their conserved nature, but because there was insufficient sequence data of reference isolates available for comparison. It is anticipated that further investigation of these loci may reveal the core subgroups of this medically important and zoonotic assemblage and also those of others. The closer, more recent, phylogenetic relationships amongst the assemblages appear to be resolved; however, more sequence data from the current loci, and possibly new loci, will be required to establish the remaining relationships.
对GenBank数据库中目前可用的十二指肠贾第虫序列进行了综述，以比较不同的基因分型位点（小亚基核糖体DNA、谷氨酸脱氢酶、磷酸丙糖异构酶和β贾第虫蛋白）识别组合和亚组合群以及推断系统发育关系的能力。总共对405条十二指肠贾第虫序列进行了分类和比对，以检查组合A和B（人畜共患病）、C和D（狗）、E（家畜）、F（猫）和G（啮齿动物）内部和之间的替换情况。研究发现，所有基因都能将分离株可重复地归类到它们的组合中，并且AI/AII亚组合群在所有位点都是稳定且可识别的。然而，组合B的亚组在一半的位点（小亚基核糖体DNA和β贾第虫蛋白）上不可重复，这不是因为它们的保守性质，而是因为可供比较的参考分离株的序列数据不足。预计对这些位点的进一步研究可能会揭示这个医学上重要的人畜共患病组合以及其他组合的核心亚组。组合之间更紧密、更新的系统发育关系似乎已经得到解决；然而，需要来自当前位点以及可能新位点的更多序列数据来建立其余的关系。
