The complete plastid genome sequence of the parasitic green alga Helicosporidium sp. is highly reduced and structured
2006
The plastid genome of the parasitic green alga Helicosporidium sp.
publication
Evidence: high
Author Information
Author(s): Audrey P. de Koning, Patrick J. Keeling
Primary Institution: University of British Columbia
Hypothesis
How does the loss of photosynthesis affect the structure and content of plastid genomes?
Conclusion
The Helicosporidium plastid genome shows a highly ordered reduction following the loss of photosynthesis, suggesting common evolutionary pressures on plastid genomes.
Supporting Evidence
- The Helicosporidium plastid genome is among the smallest known at 37.5 kb.
- It lacks all genes for photosynthesis and has minimal non-coding DNA.
- The genome is highly structured, with nearly all genes on one strand.
- Helicosporidium is related to trebouxiophyte green algae but has a genome more like that of apicomplexan parasites.
Takeaway
Helicosporidium is a tiny alga that lost its ability to photosynthesize, and its DNA is now very small and organized in a special way.
Methodology
The complete plastid genome was sequenced and analyzed for gene content and structure.
Limitations
The study is limited by the small number of fully sequenced non-photosynthetic plastid genomes for comparison.
Digital Object Identifier (DOI)
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