Giardia lamblia is a widely concerned archezoan. In order to study the phylogeny of G.lamblia, ITS(1 and 2) of ribosome gene(rDNA) and 5.8 SrDNA from various Giardia strains were amplified,cloned and sequenced. A mole...Giardia lamblia is a widely concerned archezoan. In order to study the phylogeny of G.lamblia, ITS(1 and 2) of ribosome gene(rDNA) and 5.8 SrDNA from various Giardia strains were amplified,cloned and sequenced. A molecular phylogenetic tree was constructed with NJ method. After analyzed by DNAMAN software, 12 bases in 2 of the 10 squences were found to be substituted and 1 of the 2 had one base deletion, while the other 8 squences were quite homologous. The constructed phylogenetic tree was consistent with the phylogenic relationship reported previously. All the results show that ITS(1 and 2) and 5.8 SrRNA genes are effective genetic markers for studies of the evolution of Giardia.展开更多
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha ...In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha sp.,and A.manca,were compared and analyzed using ITS2 secondary structures,ITS1-5.8S-ITS2 region and SSrRNA gene sequences.The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced,and they shared sequence identities ranging from 68.0% to 90.1%,while two populations of Anteholosticha sp.differed in three nucleotides（sequence identity 99.8%）.There were several minor differences among ITS2 secondary structures of these species,while two populations of Anteholosticha sp.had the identical secondary structure.Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms（Neighbor-Joining,Maximum Parsimony and Bayesian） revealed similar topologies.The results show that：（1） Holosticha bradburyae and H.diademata firmly clustered together with strong bootstrap supports,forming a sister clade with Anteholosticha sp.,（2） Anteholosticha appeared to be a paraphyletic assemblage,in which the morphotype A.manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp.Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha,nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.展开更多
文摘Giardia lamblia is a widely concerned archezoan. In order to study the phylogeny of G.lamblia, ITS(1 and 2) of ribosome gene(rDNA) and 5.8 SrDNA from various Giardia strains were amplified,cloned and sequenced. A molecular phylogenetic tree was constructed with NJ method. After analyzed by DNAMAN software, 12 bases in 2 of the 10 squences were found to be substituted and 1 of the 2 had one base deletion, while the other 8 squences were quite homologous. The constructed phylogenetic tree was consistent with the phylogenic relationship reported previously. All the results show that ITS(1 and 2) and 5.8 SrRNA genes are effective genetic markers for studies of the evolution of Giardia.
基金The Natural Science Foundation of China under contract No. 30870264the Center of Excellence in Biodiversity,King Saud University,Saudi Arabia
文摘In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates,Holosticha-complex,four closely related holostichids（five populations）,Holosticha bradburyae,H.diademata,Anteholosticha sp.,and A.manca,were compared and analyzed using ITS2 secondary structures,ITS1-5.8S-ITS2 region and SSrRNA gene sequences.The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced,and they shared sequence identities ranging from 68.0% to 90.1%,while two populations of Anteholosticha sp.differed in three nucleotides（sequence identity 99.8%）.There were several minor differences among ITS2 secondary structures of these species,while two populations of Anteholosticha sp.had the identical secondary structure.Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms（Neighbor-Joining,Maximum Parsimony and Bayesian） revealed similar topologies.The results show that：（1） Holosticha bradburyae and H.diademata firmly clustered together with strong bootstrap supports,forming a sister clade with Anteholosticha sp.,（2） Anteholosticha appeared to be a paraphyletic assemblage,in which the morphotype A.manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp.Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha,nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.
