Selfish migrants: How a meiotic driver is selected to increase dispersal

Area of Science:

• Genetics
• Evolutionary Biology
• Behavioral Ecology

Background:

• Meiotic drivers are selfish genetic elements that bias their own inheritance during meiosis.
• The t haplotype in house mice is a well-studied meiotic driver with inherent fitness costs, such as reduced viability and fertility.
• Previous research has not fully explained how the t haplotype's negative traits are maintained despite its meiotic drive advantage.

Purpose of the Study:

• To investigate the evolutionary mechanisms by which the t haplotype influences mouse dispersal.
• To determine if the t haplotype's deleterious traits can select for increased dispersal in carriers.
• To model the relationship between meiotic drive, genetic disadvantages, and dispersal behavior.

Main Methods:

• Development of individual-based models incorporating dispersal loci on t and wildtype chromosomes.
• Simulation of density-dependent gene expression for dispersal traits.
• Analysis of model variants to assess the impact of t haplotype's specific fitness costs (polyandry disadvantage, homozygote inviability/sterility) on dispersal evolution.

Main Results:

• The t haplotype consistently evolves to enhance dispersal propensity in its carriers, especially under high population densities.
• The increase in dispersal is driven by the t haplotype's deleterious traits, acting as a selective pressure.
• Dispersal evolution is robust across a range of meiotic driver strengths and associated fitness disadvantages.

Conclusions:

• Increased dispersal by t-carriers is an adaptive strategy driven by the t haplotype's own genetic disadvantages.
• This behavioral adaptation may explain the persistence of meiotic drivers like the t haplotype in natural populations.
• The findings highlight the complex interplay between meiotic drive, genetic load, and host behavior in shaping evolutionary trajectories.