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Next-generation Sequencing of 16S Ribosomal RNA Gene Amplicons
Published on: August 29, 2014
Ribosomal External and Internal Transcribed Spacers: Combined Use in the Phylogenetic Analysis of Medicago
1Institut de Biotechnologie des Plantes, Université Paris-Sud, Bâtiment 630, F-91405 Orsay Cedex France
Journal of Molecular Evolution
|March 18, 1998
Summary
The nuclear ribosomal external transcribed spacer (ETS) evolves faster and is more informative than the internal transcribed spacer (ITS) for plant phylogeny. Analyzing both spacers together maximizes phylogenetic resolution in Medicago species.
Area of Science:
- * Molecular evolution
- * Plant systematics
- * Phylogenetics
Background:
- * The nuclear ribosomal DNA (rDNA) region, comprising internal transcribed spacer (ITS) and external transcribed spacer (ETS) sequences, is widely used in plant phylogenetic studies.
- * Understanding the evolutionary dynamics of these spacers is crucial for accurate phylogenetic inference.
- * The genus Medicago (Fabaceae) presents an interesting case for phylogenetic analysis due to its complex evolutionary history.
Purpose of the Study:
- * To evaluate the phylogenetic utility of the ribosomal ETS in the genus Medicago.
- * To compare the evolutionary rates and informativeness of ETS versus ITS.
- * To construct a robust phylogeny for Medicago species using combined ETS and ITS data.
Main Methods:
- * Sequencing of the ETS region from 13 annual Medicago species.
- * Comparative analysis of evolutionary rates between ETS and ITS.
- * Phylogenetic analyses utilizing both ETS and ITS sequences.
Main Results:
- * The ETS evolved 1.5 times faster and was 1.5 times more informative than ITS in Medicago.
- * Reduced constraints during ribosomal maturation are proposed as the reason for differential evolutionary rates.
- * Combined analysis of ETS and ITS yielded maximal phylogenetic resolution and support, with no incongruence detected.
- * The resulting phylogeny indicated that none of the studied Medicago subsections were monophyletic.
Conclusions:
- * Ribosomal ETS is a valuable molecular marker for enhancing plant phylogeny, particularly in the genus Medicago.
- * Analyzing ETS alongside ITS provides a more robust and resolved phylogenetic framework.
- * The phylogenetic analysis of Medicago suggests a non-monophyletic structure for its subsections.
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