Project description:Investigation of genome-wide gene expression in sepals, petals, stamens, staminodia and carpels in pre-anthesis Aquilegia flowers. One goal was to identify transcriptional signatures associated with petaloidy by comparing gene expression in petals and petaloid sepals. Other goals were to study the evolutionary origin and ecological function of staminodia by comparing a) expression patterns in stamens, staminodia and carpels, b) identifying transcriptional regulators expressed in staminodia and c) using gene set enrichment analysis to identify biological processes operating in staminodia.
Project description:Investigation of genome-wide gene expression in sepals, petals, stamens, staminodia and carpels in pre-anthesis Aquilegia flowers. One goal was to identify transcriptional signatures associated with petaloidy by comparing gene expression in petals and petaloid sepals. Other goals were to study the evolutionary origin and ecological function of staminodia by comparing a) expression patterns in stamens, staminodia and carpels, b) identifying transcriptional regulators expressed in staminodia and c) using gene set enrichment analysis to identify biological processes operating in staminodia. A 15 chip study using total RNA from the five floral tissues from three replicate natural populations with each sample representing tissue pooled from 60 flowers.
Project description:We report the investigation of an Aquilegia flavescens × A. formosa population in British Columbia that is disjunct from its parents-the latter species is present locally but ecologically separated, while the former is entirely absent. To confirm hybridity, we used multivariate analysis of floral characters of field-sampled populations to ordinate phenotypes of putative hybrids in relation to those of the parental species. Microsatellite genotypes at 11 loci from 72 parental-type and putative hybrid individuals were analysed to assess evidence for admixture. Maternally inherited plastid sequences were analysed to infer the direction of hybridization and test hypotheses on the origin of the orphan hybrid population. Plants from the orphan hybrid population are on average intermediate between typical A. formosa and A. flavescens for most phenotypes examined and show evidence of genetic admixture. This population lies beyond the range of A. flavescens, but within the range of A. formosa. No pure A. flavescens individuals were observed in the vicinity, nor is this species known to occur within 200 km of the site. The hybrids share a plastid haplotype with local A. formosa populations. Alternative explanations for this pattern are evaluated. While we cannot rule out long-distance pollen dispersal followed by proliferation of hybrid genotypes, we consider the spread of an A. formosa plastid during genetic swamping of a historical A. flavescens population to be more parsimonious.