Gene Conversion Facilitates Adaptive Evolution on Rugged Fitness Landscapes

Area of Science:

• Evolutionary biology
• Genetics
• Molecular evolution

Background:

• Gene conversion facilitates genetic exchange between homologous DNA, crucial for maintaining gene families in organisms.
• Understanding gene conversion's role in single gene evolution with duplicates is essential.

Purpose of the Study:

• To investigate how gene conversion with a silenced duplicate impacts the evolutionary speed of a functional gene.
• To analyze the influence of gene conversion frequency and landscape structure on adaptation.

Main Methods:

• Utilized two distinct models of evolution on rugged fitness landscapes.
• Employed analytical and numerical approaches, including stochastic effects in finite populations.

Main Results:

• Gene conversion with a passive duplicate significantly speeds up adaptation by circumventing low-fitness valleys.
• Adaptation speed depends non-trivially on gene conversion frequency and landscape structure.
• An optimal gene conversion rate was identified, maximizing adaptation speed in both deterministic and stochastic models.

Conclusions:

• Duplicate genes can serve as 'scratch paper,' enabling evolution beyond solely beneficial mutations.
• Gene conversion with duplicates offers a powerful mechanism for accelerated adaptation in challenging selective environments.