The population genetics of the self-incompatibility polymorphism in Papaver rhoeas. VI. Estimation of the overlap between the allelelic complements of a pair of populations

O'Donnell, S; Lane, Meredith; Lawrence, Michael

doi:10.1038/hdy.1993.183

Cited by 23 publications

(16 citation statements)

References 11 publications

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“…Whilst we cannot categorically rule out this argument, there are considerable phenotypic differences between cv. Shirley and the wild-type plants and more importantly, our cross-classification studies have revealed that the British populations analysed contain essentially the same complement of S alleles [15,18], whereas the Spanish population contains a significantly different subset [ 12], which is consistent with the populations being separated for a considerable period. Moreover, the sequence analysis revealed a number of base pair substitutions in the flanking regions of the open reading frame.…”

Section: Discussionsupporting

confidence: 63%

Molecular analysis of two functional homologues of the S 3 allele of the Papaver rhoeas self-incompatibility gene isolated from different populations

et al. 1996

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The S3 allele of the S gene has been cloned from Papaver rhoeas cv. Shirley. The sequence predicts a hydrophilic protein of 14.0 kDa, showing 55.8% identity with the previously cloned S1 allele, preceded by an 18 amino acid signal sequence. Expression of the S3 coding region in Escherichia coli produced a form of the protein, denoted S3e, which specifically inhibited S3 pollen in an in vitro bioassay. The recombinant protein was ca. 0.8 kDa larger than the native stigmatic form, indicating post-translational modifications in planta, as was previously suggested for the S1 protein. In contrast to other S proteins identified to date, S3 protein does not appear to be glycosylated. Of particular significance is the finding that despite exhibiting a high degree of sequence polymorphism, secondary structure predictions indicate that the S1 and S3 proteins may adopt a virtually identical conformation. Sequence analysis also indicates that the S1 and S3 proteins may adopt a virtually identical conformation. Sequence analysis also indicates that the P. rhoeas S alleles share some limited homology with the SLG and SRK genes from Brassica oleracea. Previously, cross-classification of different populations of P. rhoeas had revealed a number of functionally identical alleles. Probing of Western blots of stigma proteins from plants derived from a wild Spanish population which contained an allele functionally identical to the Shirley S3 allele with antiserum raised to S3e, revealed a protein (S3s) which was indistinguishable in pI and Mr from that in the Shirley population. A cDNA encoding S3s was isolated, nucleotide sequencing revealing a coding region with 99.4% homology with the Shirley-derived clone at the DNA level, and 100% homology at the amino acid level.

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Section: Discussionsupporting

confidence: 63%

Molecular analysis of two functional homologues of the S 3 allele of the Papaver rhoeas self-incompatibility gene isolated from different populations

et al. 1996

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“…Secondly, these results confirm a point that we have made in previous papers, namely, that while the selective advantage of an allele is negatively related to its frequency in the population, it is also negatively related to the number of alleles present (Campbell & Lawrence, 1981a;Lane and Lawrence, 1993;O'Donnell et al, 1993). In consequence, the strength of the frequency-dependent selection becomes progressively attenuated as the number of alleles in the population increases.…”

Section: Discussionsupporting

confidence: 78%

The population genetics of the self-incompatibility polymorphism in Papayer rhoeas. VIII. Sampling effects as a possible cause of unequal allele frequencies

et al. 1994

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This paper considers the hypothesis that the unequal S-allele frequencies in the British populations of Papaver rhoeas we have examined are caused by a sampling effect over and above that due to drift. The results obtained by simulating the polymorphism on the computer show that it takes between 70 and 80 non-overlapping generations before stochastic equilibrium is achieved with respect to allele frequency in a population of size 3720 containing 31 alleles, both when the frequencies of the alleles are initially as unequal as they were in the R106 sample (Campbell & Lawrence, 198 ib) and when these frequencies are exactly equal. These results show that the strength of the frequency-dependent selection that maintains the polymorphism becomes very considerably attenuated as the number of alleles in the population increases. A review of the relevant genetical and ecological evidence suggests that the size of the British populations is considerably larger than the minimum required to maintain the number of alleles they are estimated to contain, so that opportunities for sampling effects to perturb the frequencies of these alleles appear to be limited. The results obtained from an investigation of the reproductive biology of the species, however, show that the distribution of progeny size is markedly non-random. It is possible that this may be the cause of the unequal allele frequencies observed in the the British populations.

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“…The number of S-alleles common to each pair of populations was estimated using the maximum likelihood method set out in O'Donnell et al (1993), then the percentage overlap in kinds of S-alleles was calculated. As a statistic for describing population differentiation at the S-locus, Wright's fixation index, F ST was calculated by the variance-based method of Weir and Cockerham (1984) using FSTAT ver.…”

Section: Discussionmentioning

confidence: 99%

Distribution of S-alleles in island populations of flowering cherry, Prunus lannesiana var. speciosa

et al. 2007

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We surveyed the distribution of S-alleles in natural island populations of Prunus lannesiana var. speciosa sampled from seven sites on the Izu Peninsula and six Izu islands, Japan. The S-genotypes of sampled individuals were determined by Southern analysis of RFLPs generated by restriction enzyme digestion of genomic DNA, using cDNA of the S-RNase gene as a probe. All individuals were heterozygous, as expected under gametophytic self-incompatibility (GSI). Sixty-three Salleles were observed in the species, but 12 private to the Izu Peninsula population seemed to be derived from related species, giving a total of 75. The estimated number of S-alleles in each population ranged from 26 to 62, and was inversely correlated with the respective population's distance from the Izu Peninsula, the closest point in the mainland to the islands. This geographical cline in the estimated numbers of S-alleles suggests that gene flow to and from the distant island populations was less frequent, and that the studied species has migrated from the mainland to the Izu islands. The genetic relationship at the S-locus among populations also gave an "isolation by distance" pattern. The genetic differentiation at the S-locus among the populations was very low (F ST = 0.014, p < 0.001). The number of S-alleles in the species did not seem to depend on genetic differences associated with population subdivisions. This might be due to the greater effective migration rates of S-alleles, as expected under balancing selection in GSI.

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The population genetics of the self-incompatibility polymorphism in Papaver rhoeas. VI. Estimation of the overlap between the allelelic complements of a pair of populations

Cited by 23 publications

References 11 publications

Molecular analysis of two functional homologues of the S 3 allele of the Papaver rhoeas self-incompatibility gene isolated from different populations

Molecular analysis of two functional homologues of the S 3 allele of the Papaver rhoeas self-incompatibility gene isolated from different populations

The population genetics of the self-incompatibility polymorphism in Papayer rhoeas. VIII. Sampling effects as a possible cause of unequal allele frequencies

Distribution of S-alleles in island populations of flowering cherry, Prunus lannesiana var. speciosa

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