Polymorphisms for purely cytoplasmically inherited traits in bisexual plants

Area of Science:

• Evolutionary biology
• Population genetics
• Genetics

Background:

• Cytoplasmic inheritance, primarily through ovules, presents unique evolutionary dynamics.
• Maintaining cytoplasmic polymorphisms without nuclear gene involvement is a key question in evolutionary genetics.

Purpose of the Study:

• To investigate the conditions under which cytoplasmic polymorphisms can be maintained solely by non-nuclear factors.
• To explore the role of sexual asymmetry and fertilization dynamics in cytoplasmic polymorphism stability.
• To compare the dynamics of cytoplasmic polymorphism with nuclear gene selection.

Main Methods:

• Mathematical modeling of cytoplasmic inheritance and population dynamics.
• Analysis of factors including sexual asymmetry, fertilization efficiency, and selfing rates.
• Comparison of cytoplasmic polymorphism models with nuclear selection models.

Main Results:

• Cytoplasmic polymorphisms can be maintained without gene-cytoplasmic interactions under specific conditions.
• Asymmetry in ovule and pollen production (sexual asymmetry), incomplete, frequency-dependent fertilization, and differential selfing rates are crucial.
• These factors create negative frequency dependence, stabilizing cytoplasmic polymorphisms.
• The model replicates dynamics seen in nuclear selection with two alleles.
• Strong sexual asymmetry facilitates stable cytoplasmic polymorphisms, but can risk population survival without nuclear interactions.

Conclusions:

• Stable cytoplasmic polymorphisms are possible through non-genetic interactions, driven by reproductive asymmetries.
• Gene-cytoplasmic interactions mitigate risks associated with solely cytoplasmic inheritance, leveraging sexual asymmetry.
• Understanding these dynamics is vital for comprehending plant population genetics and evolution.