title: A homozygous S genotype of Brassica oleracea expresses two S-like genes.
abstract: The sporophytic self-incompatibility system of Brassica species is controlled by a single locus, S. Recognition of self between pollen and stigma is probably mediated by S locus-specific glycoproteins (SLSGs). We describe the isolation, from an S29 homozygote of Brassica oleracea, of two different cDNA clones for transcripts which are equally abundant in stigmas competent for self-incompatibility and each of which is homologous to previously reported SLSG sequences. Extensive DNA sequence divergence between the two clones precludes their cross-hybridisation and each acts as a gene-specific probe. All S genotypes appear to have a single copy of each gene but there are significantly different levels of polymorphism associated with each. The clear structural homology between the two indicates a gene duplication involving the S locus and, perhaps, related to the evolution of self-incompatibility.
authors.affiliation: Institute of Plant Science Research, Cambridge Laboratory, Trumpington, UK.
authors.forename: M
authors.initials: M
authors.lastname: Trick
authors.forename: R B
authors.initials: RB
authors.lastname: Flavell
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D001937:Brassica / Q000235:genetics* / Q000502:physiology; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D004251:DNA Transposable Elements; D005786:Gene Expression Regulation; D014644:Genetic Variation; D005838:Genotype; D006720:Homozygote; D008969:Molecular Sequence Data; D010641:Phenotype; D011110:Polymorphism, Genetic; D014158:Transcription, Genetic
chemical_list: D004251:DNA Transposable Elements; D004247:DNA