Admixture, evolution, and variation in reproductive isolation in the Boechera puberula clade

Area of Science:

• Plant evolutionary biology
• Genomics
• Speciation

Background:

• Hybridization and admixture are common in plants, potentially blurring species boundaries but also increasing genetic variation.
• The genus Boechera exemplifies extensive hybridization with numerous hybrid derivatives across varying ploidy levels.
• Previous studies on Boechera admixture have lacked a genomic-scale perspective.

Purpose of the Study:

• To clarify the evolutionary history of the Boechera puberula clade using genomic data.
• To assess admixture patterns and reproductive isolation within the B. puberula group and related species.
• To investigate the genomic basis of hybridization in Boechera.

Main Methods:

• Genotyping-by-Sequencing (GBS) was employed to analyze genetic variation.
• 14,815 common genetic variants were identified and analyzed.
• Patterns of admixture and reproductive isolation were inferred from genetic data.

Main Results:

• Evidence for hybridization was found within the Boechera puberula clade and with B. stricta and B. retrofracta.
• Both recent and ancient admixture events were detected, with varying levels across species.
• The B. puberula group shows evidence of a monophyletic origin and a split into two subspecies.

Conclusions:

• Reproductive isolation does not accumulate linearly with divergence time in this system.
• Admixture plays a significant role in the evolution of Boechera species.
• The interplay of sexuality and asexuality influences evolutionary trajectories in Boechera.