title: Transcriptomic shock generates evolutionary novelty in a newly formed, natural allopolyploid plant.
abstract: New hybrid species might be expected to show patterns of gene expression intermediate to those shown by parental species. "Transcriptomic shock" may also occur, in which gene expression is disrupted; this may be further modified by whole genome duplication (causing allopolyploidy). "Shock" can include instantaneous partitioning of gene expression between parental copies of genes among tissues. These effects have not previously been studied at a population level in a natural allopolyploid plant species. Here, we survey tissue-specific expression of 144 duplicated gene pairs derived from different parental species (homeologs) in two natural populations of 40-generation-old allotetraploid Tragopogon miscellus (Asteraceae) plants. We compare these results with patterns of allelic expression in both in vitro "hybrids" and hand-crossed F(1) hybrids between the parental diploids T. dubius and T. pratensis, and with patterns of homeolog expression in synthetic (S(1)) allotetraploids. Partitioning of expression was frequent in natural allopolyploids, but F(1) hybrids and S(1) allopolyploids showed less partitioning of expression than the natural allopolyploids and the in vitro "hybrids" of diploid parents. Our results suggest that regulation of gene expression is relaxed in a concerted manner upon hybridization, and new patterns of partitioned expression subsequently emerge over the generations following allopolyploidization.
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL 32611, USA. r.buggs@qmul.ac.uk
authors.forename: Richard J A
authors.initials: RJ
authors.lastname: Buggs
authors.forename: Linjing
authors.initials: L
authors.lastname: Zhang
authors.forename: Nicholas
authors.initials: N
authors.lastname: Miles
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Tate
authors.forename: Lu
authors.initials: L
authors.lastname: Gao
authors.forename: Wu
authors.initials: W
authors.lastname: Wei
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Schnable
authors.forename: W Brad
authors.initials: WB
authors.lastname: Barbazuk
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Soltis
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Soltis
mesh_terms: D005075:Biological Evolution; D018744:DNA, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020131:Genes, Duplicate; D018745:Genome, Plant; D006824:Hybridization, Genetic; D016133:Polymerase Chain Reaction; D011123:Polyploidy; D031188:Tragopogon / Q000235:genetics*; D059467:Transcriptome
chemical_list: D018744:DNA, Plant