Decoupled evolution of coding region and mRNA expression patterns after gene duplication: implications for the...

Area of Science:

• Molecular evolution
• Genomics
• Systems biology

Background:

• The neutralist theory posits that most mutations are neutral or deleterious, predicting clock-like divergence rates for retained duplicate genes.
• This prediction is typically assessed for coding sequences but can also apply to gene expression patterns.
• A correlation between sequence divergence and expression pattern divergence is expected if both evolve at similar rates.

Purpose of the Study:

• To test the prediction of correlated divergence rates between coding sequences and mRNA expression patterns for duplicate genes.
• To investigate the evolutionary rates of sequence and expression patterns in Saccharomyces cerevisiae duplicate gene pairs.
• To assess the implications for the neutralist-selectionist debate in molecular evolution.

Main Methods:

• Analysis of a large sample of duplicate gene pairs in Saccharomyces cerevisiae.
• Utilizing genome sequence data to assess coding sequence divergence.
• Employing microarray expression data to quantify divergence in mRNA expression patterns.

Main Results:

• A weak correlation was observed between the sequence divergence and expression pattern divergence of duplicate gene pairs.
• This suggests that coding sequences and mRNA expression patterns evolve largely independently.
• The rates of evolution for sequence and expression patterns differ significantly.

Conclusions:

• The independent evolution of coding sequences and expression patterns challenges the neutralist prediction of clock-like, correlated divergence.
• The findings suggest that different evolutionary pressures and mechanisms may govern sequence and expression evolution.
• This study contributes to the ongoing debate between neutralist and selectionist explanations for molecular evolution.