Molecular Ecology and Evolution
Paape, Timothy .
Molecular evolutionary analysis of self-incompatibility in the Papaveraceae.
I am examining the genealogical history and population genetics of the gametophytic self-incompatibility (GSI) locus of the Papaveraceae plant family. The S-locus in this family has previously been characterized at the molecular level in two species, Papaver rhoeas and P. nudicaule. Molecular data from these species enabled the amplification of 39 sequences that represent potential alleles from a homologous S-locus from Argemone munita, Romneya coulteri and Platystemon californicus, all of which are California natives. The S-locus of this family represents a non-homologous system of self-recognition from other plant families possessing GSI including the Rosaceae, Solanaceae, and Scrophulariaceae. I am currently conducting population-wide studies in the three California species which will determine the number of alleles and level of sequence divergence within each sampled species. Previous studies of S-loci have revealed extensive trans-specific evolution in which the age of the alleles often pre-dates the speciation event that separated various taxa. Preliminary genealogical analyses have showed that the potential S-alleles from the California species exhibit an overall lower range of diversity than the four published Papaver alleles. I will sample natural populations of P. rhoeas from both Great Britain and Spain to obtain sequence data of S-alleles and perform genealogical reconstructions and compare allelic divergence in this and other genera. Sequence data from several species, including P. rhoeas, will also enable the detection of the effects of positive selection upon the S-locus by estimating non-synonymous vs. synonymous nucleotide substitution rates at various sites. Historical and demographic inferences can also be made regarding population size from S-allele number and genealogies. Lastly, I will assess the site of inhibition of pollen tube growth in several genera with diverse floral designs using fluorescence microscopy. Little is known about the site and timing of pollen tube inhibition in this family outside the genus Papaver. -DU
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1 - University of California San Diego, Biology-EBE, Kohn Lab, 9500 Gilman Dr., La Jolla, California, 92093-0116, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 31st, 2006
Time: 2:30 PM