title: Inferences on the number and frequency of S-pollen gene (SFB) specificities in the polyploid Prunus spinosa.
abstract: In flowering plants, self-incompatibility is a genetic mechanism that prevents self-fertilization. In gametophytic self-incompatibility (GSI), pollen specificity is encoded by the haploid genotype of the pollen tube. In GSI, specificities are maintained by frequency-dependent selection, and for diploid species, at equilibrium, equal specificity frequencies (isoplethy) are expected. This prediction has been tested in diploid, but never in polyploid self-incompatible species. For the latter, there is no theoretical expectation regarding isoplethy. Here, we report the first empirical study on specificity frequencies in a natural population of a polyploid self-incompatible species, Prunus spinosa. A total of 32 SFB (the pollen S gene) putative specificities are observed in a large sample from a natural population. Although P. spinosa is polyploid, the number of specificities found is similar to that reported for other diploid Rosaceae species. Unequal specificity frequencies are observed.
authors.affiliation: 1Molecular Evolution Group, Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal.
authors.forename: J
authors.initials: J
authors.lastname: Vieira
authors.forename: R A M
authors.initials: RA
authors.lastname: Santos
authors.forename: S M
authors.initials: SM
authors.lastname: Ferreira
authors.forename: C P
authors.initials: CP
authors.lastname: Vieira
mesh_terms: D000483:Alleles; D005787:Gene Frequency; D005828:Genetics, Population; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D011058:Pollen / Q000235:genetics*; D011123:Polyploidy; D027861:Prunus / Q000145:classification / Q000235:genetics*; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D010940:Plant Proteins