title: Nonadditive gene expression in polyploids.
abstract: Allopolyploidy involves hybridization and duplication of divergent parental genomes and provides new avenues for gene expression. The expression levels of duplicated genes in polyploids can show deviation from parental additivity (the arithmetic average of the parental expression levels). Nonadditive expression has been widely observed in diverse polyploids and comprises at least three possible scenarios: (a) The total gene expression level in a polyploid is similar to that of one of its parents (expression-level dominance); (b) total gene expression is lower or higher than in both parents (transgressive expression); and (c) the relative contribution of the parental copies (homeologs) to the total gene expression is unequal (homeolog expression bias). Several factors may result in expression nonadditivity in polyploids, including maternal-paternal influence, gene dosage balance, cis- and/or trans-regulatory networks, and epigenetic regulation. As our understanding of nonadditive gene expression in polyploids remains limited, a new generation of investigators should explore additional phenomena (i.e., alternative splicing) and use other high-throughput "omics" technologies to measure the impact of nonadditive expression on phenotype, proteome, and metabolome.
authors.affiliation: Department of Biology, University of Florida, Gainesville, Florida 32611-8525; email: ymj@ufl.edu , xiaoxianliu@ufl.edu , dsoltis@ufl.edu.
authors.forename: Mi-Jeong
authors.initials: MJ
authors.lastname: Yoo
authors.forename: Xiaoxian
authors.initials: X
authors.lastname: Liu
authors.forename: J Chris
authors.initials: JC
authors.lastname: Pires
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Soltis
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Soltis
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics; D044127:Epigenesis, Genetic; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D018745:Genome, Plant; D006824:Hybridization, Genetic; D011123:Polyploidy
keywords: additivity; alternative splicing; expression-level dominance; genome duplication; homeolog expression bias; transgressive expression