Unifying framework explaining how parental regulatory divergence can drive gene expression in hybrids and...

Area of Science:

• Genetics
• Evolutionary Biology
• Molecular Biology

Background:

• Hybridization and polyploidy are significant evolutionary mechanisms driving phenotypic changes.
• Observed outcomes include non-additive gene expression, subgenome dominance, altered genomic dosage, and transcriptome downsizing.
• The universality and adaptive nature of these responses to genome merging remain under investigation.

Purpose of the Study:

• To develop a thermodynamic model of gene expression based on transcription factor (TF)-promoter binding.
• To differentiate the effects of hybridization from polyploidy.
• To explain phenotypic patterns in hybrids and polyploids.

Main Methods:

• A thermodynamic model was developed based on transcription factor (TF)-promoter binding dynamics.
• The model was applied to interspecific hybridization scenarios with divergent gene expression, cell volume, or euchromatic ratios.
• The model's predictions were compared with empirical observations.

Main Results:

• Gene regulation patterns in hybrids and polyploids largely result from the interplay of inherited, diverged regulatory networks.
• Subsequent adaptive evolution appears to play a lesser role in these patterns.
• Phenotypic traits depend on specific assumptions regarding TF-promoter coevolution and nucleoplasmic distribution.

Conclusions:

• The legacy of divergent parental species directly shapes the phenotypic traits of hybrids and allopolyploids.
• The developed model provides a mechanistic explanation for observed gene expression patterns.
• Further research can explore TF-promoter coevolution and nucleoplasmic distribution to understand underlying mechanisms.