THE POPULATION-GENETICS OF THE SELF-INCOMPATIBILITY POLYMORPHISM IN PAPAVER RHOEAS .7. THE NUMBER OF S-ALLELES IN THE SPECIES

The results obtained from the cross-classification of the S-alleles of a sample of 30 plants raised from the seed taken from a Spanish population against those of a sample taken from a British population revealed that 24 alleles of the former also occurred in the latter, giving an estimated overlap of 53 per cent between the allelic complements of these populations. These data indicate that the number of alleles in the species is unlikely to be much greater than 66. It is argued that the number of alleles in the species may be subject to a dynamic restraint on the number of alleles contained in its constituent populations and possibly, also, by a molecular restraint on the allelic diversity of the S-gene.