Additive variation maintained under stabilizing selection: a two-locus model of pleiotropy for two quantitative...

Area of Science:

• Quantitative genetics
• Evolutionary biology
• Population genetics

Background:

• Pleiotropy, where one gene affects multiple traits, is common in evolution.
• Understanding the genetic basis of correlated traits is crucial for evolutionary studies.

Purpose of the Study:

• To develop a genetic model for two additive quantitative characters influenced by pleiotropic loci.
• To investigate the conditions for maintaining genetic variation under stabilizing selection.

Main Methods:

• A theoretical model with two diallelic loci controlling two additive quantitative characters was proposed.
• One locus exhibits a similar effect on both characters, while the second shows an antagonistic effect.
• Direct stabilizing selection was applied to both characters.

Main Results:

• The model predicts a stable polymorphic equilibrium, preserving genetic variation for both characters.
• Despite pleiotropic effects, the genetic correlation between the two characters at equilibrium is zero.
• The interplay between similar and antagonistic pleiotropy can lead to trait decoupling.

Conclusions:

• A model with specific pleiotropic effects can maintain genetic variation in multiple traits.
• Zero genetic correlation can arise even with pleiotropic genes under stabilizing selection.
• This highlights complex evolutionary dynamics in quantitative trait genetics.