Mate competition and evolutionary outcomes in genetically modified zebrafish (Danio rerio)

Area of Science:

• Evolutionary Biology
• Sexual Selection
• Genetics

Background:

• Understanding the interplay between sexual selection and trait evolution is crucial for evolutionary theory.
• Genetically modified organisms (GMOs) present unique challenges when they interact with wild populations.

Purpose of the Study:

• To investigate the evolutionary consequences of conflicting sexual selection mechanisms on a transgenic zebrafish (Glofish®) phenotype.
• To determine if male mating competition influences the persistence of the transgenic trait.

Main Methods:

• Mating trials comparing wild-type and transgenic male zebrafish for competitive mating success.
• Long-term population study tracking the frequency of the transgenic phenotype over 15 generations.
• Demographic modeling using fitness component data to predict phenotype loss.

Main Results:

• Wild-type males exhibited superior aggression and sired 2.5 times more offspring than transgenic males in competitive settings.
• The transgenic phenotype rapidly declined in frequency, disappearing in most populations within 15 generations.
• Male mating success was identified as the key fitness component driving the loss of the transgenic trait.

Conclusions:

• Sexual selection, specifically male-male competition, can lead to the rapid elimination of transgenic phenotypes from wild populations.
• A predictive demographic model accurately reflected the observed rate of transgenic trait loss.
• Findings have implications for assessing the evolutionary impact of escaped or released GMOs.