Effects of population size and metapopulation dynamics on a mating-system polymorphism

Area of Science:

• Evolutionary Biology
• Population Genetics
• Plant Reproduction

Background:

• The Wright-Fisher model explains neutral allele dynamics.
• Metapopulation dynamics and population turnover affect genetic diversity.
• Mating system evolution is influenced by selfing and outcrossing rates.

Purpose of the Study:

• To simulate the effects of finite population size and metapopulation dynamics on mating system polymorphism.
• To model the interplay of inbreeding depression and pollen discounting in annual plants.
• To investigate evolutionary dynamics in Eichhornia paniculata and generalizable species.

Main Methods:

• Computer simulations of a mating system model.
• Incorporation of finite population size and metapopulation dynamics.
• Modeling of selfing, outcrossing, inbreeding depression, and pollen discounting.

Main Results:

• Frequency-dependent inbreeding depression and pollen discounting observed in finite populations.
• Selfers exhibited a fixation bias due to drift, even at neutral loci.
• Metapopulation turnover favored outcrossing morphs by reducing selfers' colony establishment.

Conclusions:

• Population size and metapopulation processes significantly alter evolutionary dynamics.
• Pollen and seed dispersal interactions are crucial in finite, dynamic populations.
• Results challenge predictions based on large, stable populations for mating system evolution.