Simon J. Hiscock

Learn More
Allopolyploidy, which involves genome doubling of an interspecific hybrid is an important mechanism of abrupt speciation in flowering plants [1-6]. Recent studies show that allopolyploid formation is accompanied by extensive changes to patterns of parental gene expression ("transcriptome shock") [7-15] and that this is likely the consequence of(More)
Self-incompatibility (SI) in Brassica species is controlled by a single polymorphic locus (S) with multiple specificities. Two stigmatically expressed genes that have been cloned from this region encode the S locus glycoprotein (SLG) and S receptor kinase (SRK). Both appear to be essential for the operation of SI. It is believed that rejection of(More)
Senecio squalidus (Oxford ragwort) is a well-known introduction to the British flora that has proved to be an extremely successful colonist over the last 150 years. Unusually for a colonizing species, S. squalidus is self-incompatible (SI). Being a member of the Asteraceae, SI in S. squalidus is expected to be sporophytic. This paper presents genetic data(More)
Unilateral pollen-pistil incompatibility within the Brassicaceae has been re-examined in a series of interspecific and intergeneric crosses using 13 self-compatible (SC, Sc) species and 12 self-incompatible (SI) species from ten tribes. SC x SC crosses were usually compatible, SI x SC crosses showed unilateral incompatibility, while SI x SI crosses were(More)
Twenty-six individuals of the sporophytic self-incompatible (SSI) weed, Senecio squalidus were crossed in a full diallel to determine the number and frequency of S alleles in an Oxford population. Incompatibility phenotypes were determined by fruit-set results and the mating patterns observed fitted a SSI model that allowed us to identify six S alleles.(More)
Siphonogamy, the delivery of nonmotile sperm to the egg via a pollen tube, was a key innovation that allowed flowering plants (angiosperms) to carry out sexual reproduction on land without the need for water. This process begins with a pollen grain (male gametophyte) alighting on and adhering to the stigma of a flower. If conditions are right, the pollen(More)
Sporophytic self-incompatibility (SSI) was studied in 11 British Senecio squalidus populations to quantify mating system variation and determine how its recent colonization of the United Kingdom has influenced its mating behavior. S allele number, frequency, and dominance interactions in populations were assessed using full diallels of controlled(More)
Angiosperm stigmas exhibit high levels of peroxidase activity when receptive to pollen. To explore possible function(s) of this peroxidase activity we investigated amounts of reactive oxygen species (ROS), particularly hydrogen peroxide, in stigmas and pollen. Because nitric oxide (NO) was recently implicated in pollen tube growth, we also investigated(More)
Interspecific hybridization is an important process through which abrupt speciation can occur. In recent years, genetic changes associated with hybrid speciation have been identified through a variety of techniques, including AFLP/SSR mapping, GISH/FISH and cDNA-AFLP differential display. However, progress in using microarray technology to analyse whole(More)
Interspecific hybridization is an important mechanism of speciation in higher plants. In flowering plants, hybrid speciation is usually associated with polyploidy (allopolyploidy), but hybrid speciation without genome duplication (homoploid hybrid speciation) is also possible, although it is more difficult to detect. The combination of divergent genomes(More)