Data from: Altered gene expression and ecological divergence in sibling allopolyploids of Dactylorhiza (Orchidaceae)
Paun, Ovidiu et al. (2011), Data from: Altered gene expression and ecological divergence in sibling allopolyploids of Dactylorhiza (Orchidaceae), Dryad, Dataset, https://doi.org/10.5061/dryad.8795
Background: Hybridization and polyploidy are potent forces that have regularly stimulated plant evolution and adaptation. Dactylorhiza majalis s.s., D. traunsteineri s.l. and D. ebudensis are three allopolyploid species of a polyploid complex formed through unidirectional (and, in the first two cases, recurrent) hybridization between the widespread diploids D. fuchsii and D. incarnata. Differing considerably in geographical extent and ecological tolerance, the three allopolyploids together provide a useful system to explore genomic responses to allopolyploidization and reveal their role in adaptation to contrasting environments. Results: Analyses of cDNA-AFLPs show a significant increase in the range of gene expression of these allopolyploid lineages, demonstrating higher potential for phenotypic plasticity than shown by either parent. Moreover, allopolyploid individuals express significantly more gene variants (including novel alleles) than their parents, providing clear evidence for an increase in biological complexity following allopolyploidization. Significantly more genetic mutations have accumulated in the older D. majalis compared with the younger D. traunsteineri since their respective formation. Conclusions: Multiple origins of these tetraploids contribute to differential patterns of gene expression with a distinct geographic structure. However, several transcripts conserved within each allopolyploid taxon differ between taxa, indicating that habitat preferences shape similar expression patterns in these independently formed allopolyploids. Statistical signals separate several adaptive transcripts, related mainly to a combination of water availability and temperature that may play a role favouring the persistence of individuals in their native environments. In addition to stabilizing the allopolyploid genome, genetic and epigenetic alterations are key determinants of the adaptive success of the new polyploid species after recurrent allopolyploidization events, potentially triggering reproductive isolation between the resulting lineages.