Transposable elements drive rapid phenotypic variation in Capsella rubella

Area of Science:

• Evolutionary biology
• Genetics
• Plant science

Background:

• Organisms need rapid phenotypic changes to adapt to environmental shifts.
• Limited genetic variation after bottlenecks poses a challenge for rapid adaptation.
• Capsella rubella, an inbreeding plant, exhibits wide distribution despite a severe genetic bottleneck.

Purpose of the Study:

• Investigate the source of rapid phenotypic variation in Capsella rubella.
• Determine the role of transposable elements (TEs) in adaptation despite limited genetic diversity.
• Understand how TEs contribute to phenotypic plasticity and evolutionary success.

Main Methods:

• Comparative analysis of TEs in Capsella rubella and Capsella grandiflora.
• Assessing the association between polymorphic TEs and gene expression variation.
• Investigating TE insertions at the FLOWERING LOCUS C (FLC) gene in natural populations.

Main Results:

• TEs are significantly enriched in C. rubella compared to its outcrossing sister species.
• 4.2% of polymorphic TEs in C. rubella correlate with altered expression of adjacent genes.
• Frequent TE insertions at FLC explain 12.5% of natural variation in flowering time, impacting mRNA stability and expression.

Conclusions:

• Transposable elements are a key source of genetic variation driving rapid phenotypic diversity in C. rubella.
• TEs facilitate adaptation to changing environments in species with limited standing genetic variation.
• Specific TE insertions, like those at FLC, can directly influence adaptive traits such as flowering time.