title: Strong Maternal Effects on Gene Expression in Arabidopsis lyrata Hybrids.
abstract: Hybridization between populations or species can have pronounced fitness consequences. Yet little is known about how hybridization affects gene regulation. Three main models have been put forward to explain gene expression patterns in hybrids: additive, dominance, or parental effects. Here, we use high throughput RNA-sequencing to examine the extent to which hybrid gene expression follows predictions by each of the three models. We performed a reciprocal crossing experiment between two differentiated populations of the perennial herb Arabidopsis lyrata and sequenced RNA in rosette leaves of 12-week-old plants grown in greenhouse conditions. The two parental populations had highly differentiated gene expression patterns. In hybrids, a majority of genes showed intermediate expression relative to that of their parental populations (i.e., additive effects), but expression was frequently more similar to the maternal than to their paternal population (i.e., maternal effects). Allele-specific expression analyses showed that in the vast majority of cases, genes with pronounced maternal effect expressed both the maternal and the paternal allele. Maternal effects on hybrid gene expression have rarely been documented previously and our study suggests it could be more common than previously assumed. Whether the maternal effect on gene expression persists to later life-stages, and whether the variation in gene expression is manifested in other aspects of the phenotype, remain to be elucidated. Our findings are relevant for understanding the consequences of outbreeding and hybridization and open up several questions for future studies.
authors.affiliation: Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden.
authors.forename: Elin
authors.initials: E
authors.lastname: Videvall
authors.affiliation: Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
authors.forename: Nina
authors.initials: N
authors.lastname: Sletvold
authors.affiliation: Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden IFM Biology, Linköping University, Linköping, Sweden.
authors.forename: Jenny
authors.initials: J
authors.lastname: Hagenblad
authors.affiliation: Plant Ecology and Evolution, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
authors.forename: Jon
authors.initials: J
authors.lastname: Ågren
authors.affiliation: Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Lund, Sweden bengt.hansson@biol.lu.se.
authors.forename: Bengt
authors.initials: B
authors.lastname: Hansson
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D056084:Genetic Fitness; D006824:Hybridization, Genetic; D010641:Phenotype; D000069600:Plant Breeding; D018515:Plant Leaves / Q000235:genetics
keywords: Arabidopsis lyrata; RNA-Seq; additive effect; gene expression; hybridization; maternal effect