Evolutionary course of CsRn1 long-terminal-repeat retrotransposon and its heterogeneous integrations into the genome of the liver fluke, Clonorchis sinensis.
(2003)
Journal - The Korean journal of parasitology (Korea (South) )
Abstract :
The evolutionary course of the CsRn1 long-terminal-repeat (LTR) retrotransposon was predicted by conducting a phylogenetic analysis with its paralog LTR sequences. Based on the clustering patterns in the phylogenetic tree, multiple CsRn1 copies could be grouped into four subsets, which were shown to have different integration times. Their differential sequence divergences and heterogeneous integration patterns strongly suggested that these subsets appeared sequentially in the genome of C. sinensis. Members of recently expanding subset showed the lowest level of divergence in their LTR and reverse transcriptase gene sequences. They were also shown to be highly polymorphic among individual genomes of the trematode. The CsRn1 element exhibited a preference for repetitive, agenic chromosomal regions in terms of selecting integration targets. Our results suggested that CsRn1 might induce a considerable degree of intergenomic variation and, thereby, have influenced the evolution of the C. sinensis genome.
| ISSN : | 0023-4001 |
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| Mesh Heading : | Animals Clonorchis sinensis DNA, Helminth Gene Dosage Phylogeny Polymorphism, Genetic RNA-Directed DNA Polymerase Retroelements Sequence Analysis, DNA Terminal Repeat Sequences analysis genetics |
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| Mesh Heading Relevant : | Evolution, Molecular Genome genetics genetics genetics |
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Divergent long-terminal-repeat retrotransposon families in the genome of Paragonimus westermani.
(2003)
Journal - The Korean journal of parasitology (Korea (South) )
Abstract :
To gain information on retrotransposons in the genome of Paragonimus westermani, PCR was carried out with degenerate primers, specific to protease and reverse transcriptase (rt) genes of long-terminal-repeat (LTR) retrotransposons. The PCR products were cloned and sequenced, after which 12 different retrotransposon-related sequences were isolated from the trematode genome. These showed various degrees of identity to the polyprotein of divergent retrotransposon families. A phylogenetic analysis demonstrated that these sequences could be classified into three different families of LTR retrotransposons, namely, Xena, Bel, and Gypsy families. Of these, two mRNA transcripts were detected by reverse transcriptase-PCR, showing that these two elements preserved their mobile activities. The genomic distributions of these two sequences were found to be highly repetitive. These results suggest that there are diverse retrotransposons including the ancient Xena family in the genome of P. westermani, which may have been involved in the evolution of the host genome.
| ISSN : | 0023-4001 |
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| Mesh Heading : | Amino Acid Sequence Animals Cloning, Molecular DNA, Helminth Molecular Sequence Data Paragonimus Phylogeny RNA-Directed DNA Polymerase Retroelements Sequence Alignment Sequence Analysis, DNA Terminal Repeat Sequences analysis chemistry genetics |
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| Mesh Heading Relevant : | Evolution, Molecular Genome genetics genetics genetics |
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