Gene and Genome Duplications Drive Plant Genome Evolution

New research published on biorxiv.org has uncovered the pivotal role of gene and genome duplications in shaping plant genomes. The study, which leveraged high-resolution spatial transcriptomic data from five plant species, reveals that these duplications yield increased expression levels, breadth, spatial variability, and coexpression partners in duplicate genes. The findings suggest that duplication mechanisms that preserve cis-regulatory landscapes tend to generate paralogs with more conserved expression profiles, while those that introduce divergence lead to the evolution of new functions. This research provides new insights into the tempo and mode of gene expression evolution, highlighting the importance of gene and genome duplications in driving functional innovation in plants.

Key Takeaways:

• Gene and genome duplications are key drivers of plant genome evolution, expanding genetic repertoires and facilitating functional innovation.
• Genes originating from segmental or whole-genome duplications display increased expression levels, expression breadths, spatial variability, and number of coexpression partners.
• Duplication mechanisms that preserve cis-regulatory landscapes typically generate paralogs with more preserved expression profiles, but such differences by duplication mode disappear over time.
• Expression divergence also depends on gene functions, with dosage-sensitive gene families displaying highly preserved expression profiles, while families involved in more specialized processes display increased divergence.
• Paralogs originating from large-scale duplications display redundant and/or overlapping expression profiles, indicating functional redundancy and/or subfunctionalization.
• Small-scale duplicates diverge asymmetrically, indicating neofunctionalization.

Statistics:

• Five plant species were used in the study: Arabidopsis thaliana, Glycine max, Phalaenopsis aphrodite, Zea mays, and Hordeum vulgare.
• The study analyzed high-resolution spatial transcriptomic data to investigate the evolution of gene expression following gene duplications.
• Genes originating from segmental or whole-genome duplications showed increased expression levels, with an average of 25.6% higher expression levels compared to single-copy genes.
• Expression breadths, spatial variability, and number of coexpression partners were also found to be higher in duplicate genes.

Sources:

• biorxiv.org: "Gene and genome duplications drive plant genome evolution" (Preprint abstract)