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 popul ation against those of a sample taken from a British population reveal ed that 24 alleles of the former also occurred in the latter, giving a n estimated overlap of 53 per cent between the allelic complements of these populations. These data indicate that the number of alleles in t he species is unlikely to be much greater than 66. It is argued that t he number of alleles in the species may be subject to a dynamic restra int 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.