Hastings Natural History Reservation

05 Mar, 09 AM - 08 Mar, 05 AM

I will examine 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, the field poppy and P. nudicaule, the Iceland poppy. The molecular data from these species has enabled the amplification of several sequences from other genera of Papaveraceae from California that represent potential alleles from a homologous S-locus. 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. Upon the confirmation of these alleles as the S-locus through controlled crosses, I will conduct population wide studies in the 3 California species that 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 (TSE) in which the age of the alleles pre-dates the speciation event that separated various taxa. The amplification of alleles from several species will allow for the construction of detailed genealogical relationships among alleles possessed by different species. Additionally, earlier crossing studies in P. rhoeas found the most unequal allele frequencies at the S-locus of any GSI species. This finding may imply that an additional effect of selection exists beyond the normal frequency dependent selection maintaining these polymorphisms. In other genera with GSI, additional effects of selection have been suggested to be either a function of the divergence among alleles (Richman 2000) or linkage of deleterious load to the S-locus (Uyenoyama 1997). Genealogical analyses may provide insight into this phenomenon in the Papaveraceae. 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. 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.

Visit #8271 @Hastings Natural History Reservation

Approved

Under Project # 5870 | Research

Population genetics and molecular evolution of Platystemon californicus self-incompatibility

graduate_student - University of California, San Diego

Reservation Members(s)

Timothy Paape Mar 5 - 8, 2006 (4 days)
Timothy Paape Mar 5 - 8, 2006 (4 days)

Reserve Resources(s) | Create Invoice

Bunk House Cottage 2 Mar 5 - 8, 2006