title: Immediate Genetic and Epigenetic Changes in F1 Hybrids Parented by Species with Divergent Genomes in the Rice Genus (Oryza).
abstract: BACKGROUND
  Inter-specific hybridization occurs frequently in higher plants, and represents a driving force of evolution and speciation. Inter-specific hybridization often induces genetic and epigenetic instabilities in the resultant homoploid hybrids or allopolyploids, a phenomenon known as genome shock. Although genetic and epigenetic consequences of hybridizations between rice subspecies (e.g., japonica and indica) and closely related species sharing the same AA genome have been extensively investigated, those of inter-specific hybridizations between more remote species with different genomes in the rice genus, Oryza, remain largely unknown.
  
  
  RESULTS
  We investigated the immediate chromosomal and molecular genetic/epigenetic instability of three triploid F1 hybrids produced by inter-specific crossing between species with divergent genomes of Oryza by genomic in situ hybridization (GISH) and molecular marker analysis. Transcriptional and transpositional activity of several transposable elements (TEs) and methylation stability of their flanking regions were also assessed. We made the following principle findings: (i) all three triploid hybrids are stable in both chromosome number and gross structure; (ii) stochastic changes in both DNA sequence and methylation occurred in individual plants of all three triploid hybrids, but in general methylation changes occurred at lower frequencies than genetic changes; (iii) alteration in DNA methylation occurred to a greater extent in genomic loci flanking potentially active TEs than in randomly sampled loci; (iv) transcriptional activation of several TEs commonly occurred in all three hybrids but transpositional events were detected in a genetic context-dependent manner.
  
  
  CONCLUSIONS
  Artificially constructed inter-specific hybrids of remotely related species with divergent genomes in genus Oryza are chromosomally stable but show immediate and highly stochastic genetic and epigenetic instabilities at the molecular level. These novel hybrids might provide a rich resource of genetic and epigenetic diversities for potential utilization in rice genetic improvements.
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Shen
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Sun
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Cao
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Samuel Manthi
authors.initials: SM
authors.lastname: Josiah
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Pang
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China; Jilin Academy of Agricultural Sciences, Changchun, China.
authors.forename: Xiuyun
authors.initials: X
authors.lastname: Lin
authors.affiliation: Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Liu
mesh_terms: D002678:Chimera / Q000235:genetics*; D032461:Chromosomes, Plant; D019175:DNA Methylation; D004251:DNA Transposable Elements / Q000235:genetics; D044127:Epigenesis, Genetic / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D049810:Genetic Speciation; D018745:Genome, Plant; D006824:Hybridization, Genetic / Q000502:physiology*; D012275:Oryza / Q000145:classification / Q000235:genetics*; D010641:Phenotype; D011003:Ploidies
chemical_list: D004251:DNA Transposable Elements