On the Number of Self-Incompatibility Alleles Maintained in Equilibrium by a Given Mutation Rate in a Population of Given Size: A Reexamination

Some twenty years ago, Emerson [1, 2] found an extraordinary number of self-incompatibility alleles (at least 37, later stated by Lewis [7] to be 45) in Oenothera organensis, a species believed to be restricted to a few relatively moist canyons in the Organ Mountains of New Mexico within an area of 33 square miles above the 6000 foot line. careful search, Emerson found 154 individuals in the four supposedly most favorable canyons. He states: On the basis of this preliminary survey, it is estimated that the entire population of this species consists of less than one thousand and very likely less than five hundred.