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High-throughput, Robust and Highly Time-flexible Method for Surface Sterilization of Arabidopsis Seeds
Published on: October 4, 2021
Dated molecular phylogenies indicate a Miocene origin for Arabidopsis thaliana
Mark A Beilstein1, Nathalie S Nagalingum, Mark D Clements
1The Arnold Arboretum of Harvard University, Jamaica Plain, MA 02138, USA. mbeilstein@tamu.edu
Summary
New fossil evidence reveals Arabidopsis thaliana diverged from its relatives much earlier than previously thought. This suggests slower evolution and provides insights into plant diversification linked to historical climate and extinction events.
Area of Science:
- Plant evolutionary biology
- Paleobotany
- Phylogenetics
Background:
- Dated molecular phylogenies are crucial for understanding species diversity and evolutionary history.
- Accurate divergence dating relies on valid fossil calibration points, which are often limited for flowering plants like Brassicaceae.
- Arabidopsis thaliana, a key plant model, has a controversial evolutionary timeline due to limited fossil data.
Purpose of the Study:
- To re-evaluate the evolutionary timeline of Arabidopsis thaliana using previously overlooked fossil evidence.
- To establish more accurate divergence dates for key splits within the Brassicaceae family.
- To investigate the tempo of gene, genomic, and developmental evolution in Arabidopsis.
Main Methods:
- Incorporation of newly considered fossil evidence into phylogenetic analyses.
- Molecular dating techniques to estimate divergence times.
- Analysis of species diversification rates.
Main Results:
- The split between Arabidopsis thaliana and Arabidopsis lyrata is estimated at approximately 13 million years ago (Mya).
- The divergence between Arabidopsis and the Brassica complex occurred around 43 Mya.
- These dates are two- to threefold older than prior estimates, suggesting slower evolutionary rates.
- A 2- to 10-fold shift in species diversification rates was detected within Brassicaceae relatives.
- Arabidopsis evolution is linked to a warming period, not cooling, and its radiation may have been impacted by the Cretaceous-Paleogene mass extinction.
Conclusions:
- Previously underestimated fossil evidence significantly revises the evolutionary timeline of Arabidopsis.
- Evolutionary processes in Arabidopsis occurred more slowly than hypothesized, with implications for genome and developmental evolution.
- The diversification of Brassicaceae and their ecological interactions, such as with pierid butterflies, are potentially linked to major geological and extinction events.
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