Unveiling the functional fate of duplicated genes through expression profiling and structural analysis

Area of Science:

• Evolutionary biology
• Genomics
• Molecular evolution

Background:

• Gene duplication is a primary driver of functional innovation and evolutionary novelty.
• Paralogues (gene copies) can be lost or retained with modified functions (subfunctionalization, neofunctionalization).
• Complex orthology relationships arise, complicating the identification of conserved ancestral functions.

Purpose of the Study:

• To investigate the "least diverged orthologue (LDO) conjecture," which posits that slower-evolving paralogues retain ancestral functions.
• To develop and apply a novel method for identifying asymmetric gene evolution after duplication.
• To analyze functional divergence across all gene families in the PANTHER database.

Main Methods:

• Developed a novel computational method to detect asymmetric evolutionary rates between paralogues.
• Applied this method to all gene families within the PANTHER database.
• Integrated structural data (1M+ proteins) and expression data (animals, plants) to assess functional divergence.

Main Results:

• Identified significant differences in evolutionary rates (branch lengths) between paralogues following gene duplication.
• These rate differences correlate with functional divergence, supporting the LDO conjecture.
• The majority of paralogues showed similar evolutionary rates, but significant asymmetries were informative.

Conclusions:

• The least diverged orthologue (LDO) generally retains the ancestral function.
• The most diverged orthologue (MDO) is more likely to acquire novel or specialized functions.
• This finding provides a predictive framework for understanding functional evolution post-gene duplication.