Consistent and idiosyncratic pleiotropy in shaping genetic correlations.

High rD values in yeast genetic correlations indicate more stable, polygenic-driven trait relationships across environments, with some correlations influenced by few large-effect loci.

• Why it matters: Understanding the stability of genetic correlations is crucial for predicting evolutionary responses and adaptation, yet the underlying architectures causing stability or change remain unclear.
• What they did: A bivariate marker effect framework was developed to distinguish background polygenic effects from large-effect loci, applied to yeast single-cell morphology data involving 100+ traits.
• The result: Traits with higher rD showed less change in genetic correlation under environmental stress, implying that polygenic architectures promote environmental stability of trait relationships.