POPULATION GENETICS OF INTRAGAMETOPHYTIC SELFING

Area of Science:

• Evolutionary Biology
• Plant Reproduction
• Population Genetics

Background:

• Intragametophytic selfing is a reproductive strategy in homosporous ferns, producing fully homozygous sporophytes from a single gametophyte.
• Understanding its genetic consequences is crucial for plant evolutionary studies.

Purpose of the Study:

• To derive the inbreeding equilibrium for populations with partial intragametophytic selfing, selfing, and outcrossing.
• To develop methods for estimating the extent of intragametophytic selfing and selfing using parent-offspring data.
• To analyze the impact of intragametophytic selfing on genetic polymorphism and disequilibrium.

Main Methods:

• Mathematical derivation of inbreeding equilibrium.
• Development of estimation procedures using parent-offspring genetic data.
• Comparison of conditions for stable polymorphism and rates of gametic disequilibrium decay.

Main Results:

• Conditions for stable polymorphism under heterozygous advantage are more restrictive with intragametophytic selfing than with selfing.
• The decay of gametic disequilibrium is slower under intragametophytic selfing compared to selfing.
• Predictions indicate less polymorphism and greater gametic disequilibrium for loci with heterozygous advantage in populations with intragametophytic selfing.

Conclusions:

• Intragametophytic selfing influences population genetic structure differently than selfing.
• Plants with intragametophytic selfing are predicted to exhibit reduced polymorphism and increased gametic disequilibrium.
• Empirical data support these predictions, highlighting the unique evolutionary role of intragametophytic selfing.