Genetic and epigenetic consequences of recent hybridization and polyploidy in Spartina (Poaceae).
To study the consequences of hybridization and genome duplication on polyploid genome evolution and adaptation, we used independently formed hybrids (Spartina x townsendii and Spartina x neyrautii) that originated from natural crosses between Spartina alterniflora, an American introduced species, and the European native Spartina maritima. The hybrid from England, S. x townsendii, gave rise to the invasive allopolyploid, salt-marsh species, Spartina anglica. Recent studies indicated that allopolyploid speciation may be associated with rapid genetic and epigenetic changes. To assess this in Spartina, we performed AFLP (amplified fragment length polymorphism) and MSAP (methylation sensitive amplification polymorphism) on young hybrids and the allopolyploid. By comparing the subgenomes in the hybrids and the allopolyploid to the parental species, we inferred structural changes that arose repeatedly in the two independently formed hybrids. Surprisingly, 30% of the parental methylation patterns are altered in the hybrids and the allopolyploid. This high level of epigenetic regulation might explain the morphological plasticity of Spartina anglica and its larger ecological amplitude. Hybridization rather than genome doubling seems to have triggered most of the methylation changes observed in Spartina anglica.
Salmon
Armel
A
UMR 118 INRA-Agrocampus Rennes, Amélioration des Plantes et Biotechnologies Végétales, Station de Génétique et Amélioration des Plantes, F-35653 Le Rheu, France.
Ainouche
Malika L
ML
Wendel
Jonathan F
JF
D019175:DNA Methylation; D018744:DNA, Plant / Q000235:genetics*; D018745:Genome, Plant; D006824:Hybridization, Genetic; D018515:Plant Leaves / Q000235:genetics; D006109:Poaceae / Q000235:genetics*; D011123:Polyploidy; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA
D018744:DNA, Plant