GENETIC-VARIATION AND RANDOM DRIFT IN AUTOTETRAPLOID POPULATIONS

The rate of decay of genetic variation is determined for randomly mati ng autotetraploid populations of finite size, and the equilibrium homo zygosity under mutation and random drift is calculated. It is shown th at heterozygosity is lost at a slower rate than in diploid populations , and that the equilibrium heterozygosity with mutation and random dri ft is higher than for diploids. Outcrossing populations as well as pop ulations that randomly self are analyzed. A method of comparing geneti c variation between autotetraploid and diploid populations is proposed . Our treatment suggests that the ''gametic homozygosity'' provides a unified approach for comparing genotypes within a population as well a s comparing genetic variation between populations with different level s of ploidy.