1. Rewards and dangers of regulatory innovation.
- Author
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Comai, Luca
- Abstract
Regulatory mutations affecting the expression level and pattern of dosage-sensitive genes can create dosage imbalance in cells affected by the expression change. The deleterious effect of dosage imbalance is higher in homozygous and lower in heterozygous individuals. Pleiotropism of regulatory mutations is possible. In addition to the dosage-sensitive trait, the mutation may engender a dominant advantageous trait. Individuals that are heterozygous for such mutations will be fitter than the homozygotes. Pleiotropism may help explain heterosis, the vigor displayed by hybrids. Hybrids are heterozygous at many loci, causing transgressive fitness compared with homozygous parents. Adaptive evolution often involves structural variation affecting genes or cis -regulatory changes that engender novel and favorable gain-of-function gene regulation. Such mutation could result in a favorable dominant trait. At the same time, the gene product could be dosage sensitive if its change in concentration disrupts another trait. As a result, the mutant allele would display dosage-sensitive pleiotropy (DSP). By minimizing imbalance while conserving the favorable dominant effect, heterozygosity can increase fitness and result in heterosis. The properties of these alleles are consistent with evidence from multiple studies that indicate increased fitness of heterozygous regulatory mutations. DSP can help explain mysterious properties of heterosis as well as other effects of hybridization. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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