Cis-regulator runaway and divergence in asexuals

Area of Science:

• Genomics
• Evolutionary Biology
• Molecular Biology

Background:

• Gene expression evolution is crucial for understanding adaptive evolution and speciation.
• New sequencing technologies fuel intensive research into genomic changes.
• Reproductive systems significantly influence evolutionary trajectories.

Purpose of the Study:

• To model gene expression evolution across species with diverse reproductive systems.
• To investigate the impact of sexual versus asexual reproduction and parthenogenesis on expression evolution.
• To identify selective processes acting on cis-regulatory regions.

Main Methods:

• Mathematical modeling of gene expression evolution.
• Analysis of cis-regulatory region dynamics under different reproductive modes.
• Simulation of processes like outcrossing, gene conversion, and recombination.

Main Results:

• Two independent selective processes on cis-regulatory regions were identified: "Enhancer Runaway" and "Enhancer Divergence."
• "Enhancer Runaway" involves enhancers associating with mutation-purged chromosomes.
• "Enhancer Divergence" leads to expression haploidization in clonal species due to homologous region divergence.

Conclusions:

• Expression evolution is shaped by distinct mechanisms acting on cis-regulatory regions, independent of organism-level adaptation.
• These processes co-occur and vary with reproductive strategies, providing a framework for understanding eukaryotic expression evolution.
• The study offers a baseline for future research on genomic diversity and speciation.