Evolution of dominance in gene expression pattern associated with phenotypic robustness.

Area of Science:

• Genetics and Evolutionary Biology
• Systems Biology
• Computational Biology

Background:

• Mendelian inheritance describes basic genetic principles, including dominance where one allele masks another.
• Classical Mendelian dominance assumes a simple one-to-one gene-phenotype relationship.
• The generalization of Mendelian dominance to complex gene regulatory networks (GRNs) and gene expression phenotypes is not well understood.

Purpose of the Study:

• To investigate whether phenotype dominance evolves beyond classical Mendelian genetics in diploid gene regulatory networks.
• To determine if complex genotype-phenotype relationships can achieve Mendelian dominance at the gene expression level.
• To explore the role of GRN evolution in establishing dominance and phenotypic robustness.

Main Methods:

• Numerical evolution of diploid GRN models with interacting genes.
• Simulation of meiosis and recombination to model inheritance and genetic mixing.
• Analysis of genotype-phenotype relationships and calculation of the degree of dominance.

Main Results:

• Group Mendelian dominance evolves in diploid GRNs, even with complex genotype-phenotype relationships.
• The degree of dominance increases with evolution, correlating with reduced phenotypic fluctuations and increased robustness to noise.
• Dominance of gene expression patterns also evolves, enhancing robustness against meiosis-induced genome mixing.

Conclusions:

• Group Mendelian dominance and gene expression pattern dominance emerge with increased phenotypic robustness to noise.
• Sexual recombination further enhances dominance and robustness, maintaining optimal fitness despite genetic differences.
• The study demonstrates the evolution of dominance in complex biological systems beyond simple Mendelian inheritance.