The Journal of Heredity 1988:79(3):179-183
© 1988 The American Genetic Association 79:179-183
research-article |
Mating Structure and the Cost of Deleterious Mutation: I. Postponing Inbreeding
Department of Mathematics and Computer Science, University of Northern lowa Cedar Falls
Address reprint requests to Prof. Campbell, Department of Mathematics and Computer Science, University of Northern lowa, Cedar Falls, IA 50614-0441.
Abstract
Mating structure governs the distribution of alleles in populations and thus the extent to which the phenotypes associated with the alleles are manifested. A mating system which initially achieves more genetic identity within individuals than between individuals enhances the probability that a finite population without reproductive excess will become extinct from a recessive lethal or semidominant lethal mutation; however, such a mating system decreases the number of deaths that will ensue if the population size is maintained by replacement of inviable progeny with individuals engendered from the entire mating pool. This is illustrated with Markov chain models for half-sib and double-first-cousin mating in populations of four individuals and by various techniques for analogous large populations. An appropriate choice of mating strategy can mitigate the effect of deleterious mutations, but the determination of which strategy is appropriate depends on how much reproductive excess is available and on the relative costs assigned to individual deaths and the extinction of a population.