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Phylogenetic and Morphological Evolution of Green Euglenophytes Based on 18S rRNA
Yanmei Wang1, Jia Feng1, Junping Lv1
1School of Life Science, Shanxi University, Taiyuan, 030006, China.
The Journal of Eukaryotic Microbiology
|September 1, 2020
Summary
This study reveals the evolutionary relationships of green euglenophytes using phylogenetic analysis and morphological data. Euglena and Euglenaria exhibit ancestral traits, suggesting they are ancient lineages within this eukaryotic group.
Area of Science:
- Evolutionary biology
- Phycology
- Molecular phylogenetics
Background:
- Green euglenophytes are ancient eukaryotes whose evolutionary history requires clarification.
- Identifying primitive characteristics is key to understanding their evolutionary trajectory.
Purpose of the Study:
- To elucidate the phylogenetic relationships among green euglenophytes.
- To reconstruct ancestral states of morphological characters to infer evolutionary origins.
Main Methods:
- Phylogenetic tree construction using the 18S rRNA gene via Bayesian inference.
- Ancestral state reconstruction based on eight morphological characters.
Main Results:
- Established phylogenetic links: Eutreptia/Eutreptiella sister groups; Lepocinclis/Phacus/Discoplastis related; Euglena/Cryptoglena/Monomorphina/Colacium related; Trachelomonas/Strombomonas related.
- Euglena was found to be non-monophyletic.
- Identified seven primitive character states, including ductile surface and absence of a lorica.
- Ancestral flagellum length could not be determined.
Conclusions:
- Euglena and Euglenaria possess all identified ancestral traits, suggesting they represent the most ancient lineages.
- The study provides a framework for understanding green euglenophyte origins and evolution.
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