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Trematode Himasthla elongata mariner element (Hemar): structure and applications
Nick K Galaktionov1, Anna I Solovyeva, Anton V Fedorov
1Department of Cytology and Histology, Faculty of Biology, St. Petersburg State University, St. Petersburg, Russia.
Summary
This study analyzes Hemar1, a transposable element in Himasthla elongata. Hemar1 contributes to genomic variability during asexual reproduction in the snail host, suggesting it plays a role in parasite evolution.
Area of Science:
- Genetics
- Molecular Biology
- Parasitology
Background:
- Transposable elements (TEs) are mobile genetic sequences that can alter host genomes.
- Mariner-like elements (MLEs) are a class of TEs found across diverse organisms.
- Understanding TE dynamics is crucial for comprehending host-parasite co-evolution and genetic diversity.
Purpose of the Study:
- To clone and characterize Hemar1, a novel mariner TE from the parasitic trematode Himasthla elongata.
- To investigate the evolutionary relationships of Hemar1 with other MLEs.
- To assess the potential role of Hemar1 in generating genomic variability within the parasite's life cycle.
Main Methods:
- Cloning and sequencing of the full-length Hemar1 element.
- Bioinformatic analysis to determine Hemar1's genomic distribution and similarity to known TEs.
- Comparative analysis with MLEs from other species, including Girardia tigrina, Caenorhabditis elegans, and Hydra.
- Screening of host genomes for Hemar1-like sequences.
- Transposon insertional display to map Hemar1 locations within the parasite genome.
Main Results:
- Hemar1 was identified as a full-length mariner TE in H. elongata with typical TE genomic distribution.
- Hemar1 shows high similarity to MLEs from G. tigrina (88% in transposase domain) and Cemar1 from C. elegans (inverted terminal repeats).
- No significant Hemar1-like sequences were found in the parasite's hosts, arguing against recent horizontal gene transfer.
- Hemar1 insertion sites were found in regions associated with clonal diversity generation in the parasite's asexual reproductive stages (rediae and cercariae).
Conclusions:
- Hemar1 is an endogenous mariner TE in H. elongata, contributing to genomic variability during asexual reproduction.
- The evolutionary position and lack of host similarity suggest Hemar1 has not undergone recent horizontal transfer in this system.
- Hemar1 likely plays a role in generating genetic diversity within the trematode parthenitae, potentially impacting adaptation and evolution.
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