Establishment of facultative sexuals

Area of Science:

• Evolutionary biology
• Population genetics
• Theoretical biology

Background:

• The evolutionary persistence of sexual reproduction remains a significant unresolved question in biology.
• Understanding the conditions favoring the emergence of sex is crucial for evolutionary theory.

Purpose of the Study:

• To investigate the conditions under which sexual reproduction, driven by a facultative sex gene, can become established in a population.
• To model the evolutionary dynamics of sex using computational approaches.

Main Methods:

• Development of an individual-based population model to simulate evolutionary scenarios.
• Analysis of gene fixation probabilities and equilibrium fitness under varying population parameters.

Main Results:

• A hypothetical facultative sex gene can become fixed if its initial selective cost is minimal.
• Population size positively correlates with equilibrium fitness, while mutation rate shows a negative correlation.
• The probability of sex gene establishment is independent of the direct fitness differential between asexual and sexual lineages.

Conclusions:

• Low initial costs are critical for the establishment of sexual reproduction via facultative genes.
• Population size and mutation rate are key factors influencing the fitness benefits of sex.
• The evolutionary advantage of sex may arise from mechanisms not directly tied to immediate fitness advantages over asexual reproduction.