Assessing sequence heterogeneity in Chlorellaceae DNA barcode markers for phylogenetic inference

Area of Science:

• Microbiology and Evolutionary Biology
• Genomics and Bioinformatics

Background:

• Chlorellaceae species are crucial for biofuel production but face taxonomic challenges due to phenotypic plasticity and morphological similarity.
• Accurate species identification and evolutionary history reconstruction are vital for Chlorellaceae research.

Purpose of the Study:

• To investigate DNA barcode marker heterogeneity in Chlorellaceae.
• To evaluate the effectiveness of different DNA markers (18S rRNA, ITS, rbcL) for phylogenetic inference.
• To determine the optimal approach for resolving Chlorellaceae evolutionary history.

Main Methods:

• Examined sequence divergence and genomic properties of 18S rRNA, ITS, and rbcL markers.
• Analyzed 655 orthologous sequences from 64 species across 31 Chlorellaceae genera.
• Assessed phylogenetic tree discordance using Robinson-Foulds distance and Shimodaira-Hasegawa tests.
• Employed a supermatrix approach combining multiple DNA markers.

Main Results:

• Significant sequence divergence and heterogeneity were observed among DNA markers.
• The supermatrix approach enhanced phylogenetic tree congruency and reduced stochastic error.
• Individual markers showed varying support for the inferred phylogenies.
• Assessing marker heterogeneity prior to phylogenetic inference is crucial.

Conclusions:

• The supermatrix approach offers a more reliable method for inferring Chlorellaceae phylogeny.
• Understanding DNA marker properties is essential for accurate species identification and evolutionary studies.
• This research provides a robust framework for Chlorellaceae evolutionary and taxonomic research.