  Beneficial reversals of dominance reduce the costs of genetic trade-offs and
can enable selection to maintain genetic variation for fitness. Beneficial
dominance reversals are characterized by the beneficial allele for a given
context (e.g. habitat, developmental stage, trait, or sex) being dominant in
that context but recessive where deleterious. This context-dependence at least
partially mitigates the fitness consequence of heterozygotes carrying one
non-beneficial allele for their context and can result in balancing selection
that maintains alternative alleles. Dominance reversals are theoretically
plausible and are supported by mounting empirical evidence. Here we highlight
the importance of beneficial dominance reversals as a mechanism for the
mitigation of genetic conflict and review the theory and empirical evidence for
them. We identify some areas in need of further research and development and
outline three methods (dominance ordination, allele-specific expression, and
allele-specific ATAC-Seq) that could facilitate the identification of
antagonistic genetic variation. There is ample scope for the development of new
empirical methods as well as reanalysis of existing data through the lens of
dominance reversals. A greater focus on this topic will expand our
understanding of the mechanisms that resolve genetic conflict and whether they
maintain genetic variation.
