Multiple Autopolyploid Arabidopsis lyrata Populations Stabilized by Long-Range Adaptive Introgression Across Eurasia

Area of Science:

• Plant evolutionary biology
• Genomics
• Speciation studies

Background:

• Polyploid lineages vary in abundance, influenced by genetics, environment, and evolutionary time.
• The Arabidopsis genus provides a model for studying polyploid origins and persistence.

Purpose of the Study:

• To investigate the origins and distribution of polyploidy in the Arabidopsis lyrata species complex.
• To identify the genetic and geographic factors contributing to polyploid establishment.

Main Methods:

• Genomic data analysis from over 400 Arabidopsis lyrata samples across Eurasia.
• Haplotype analysis using synthetic long-read assemblies.
• Comparative analysis of meiotic adaptation genes.

Main Results:

• Arabidopsis lyrata is the most polyploid-rich species complex in its genus, with multiple autotetraploidy origins.
• Over 30 new autotetraploid populations discovered in Siberia, with at least two independent origins.
• Siberian tetraploids exhibit meiotic adaptations at the same genes as European tetraploids, despite divergence.
• Evidence of long-range introgression of adaptive alleles from European tetraploids to Siberian tetraploids.

Conclusions:

• Polyploid establishment is facilitated by meiotic adaptations and adaptive introgression, both within and between species.
• Geographic separation does not preclude the evolution of similar polyploidization mechanisms.
• The study highlights the dynamic nature of polyploid evolution and its drivers.