INHOMOGENEOUS MARKOV-CHAIN MODEL OF GENETIC DRIFT IN FINITE AUTOTETRAPLOID POPULATIONS

An inhomogeneous discrete Markov model of genetic drift in finite auto tetraploid populations with random mating is developed. The population s are monoecious, with two alleles at one locus. There is a given prob ability of self-fertilization. The generations are assumed to be non-o verlapping. The transition probability matrices are defined on the gen otype level. The population size may be varied from generation to gene ration, allowing an exact statistical description of bottlenecks. Aver age genotypic frequencies, standard deviations and probabilities of fi xation in homozygosis are calculated. Agreement is found with the clas sical theory by Wright (1938, Proc, natn. Acad. Sci. U.S.A. 24, 372-37 7). The Markov model is also verified by some numerical Monte Carlo si mulations.