Inbreeding under a cyclical mating system

• Published in: Theoretical and applied genetics 1987-02, Vol.73 (4), p.506-515
• Main Authors: Farid, A, Makarechian, M, Strobeck, C
• Format: Article
• Language: English
• Subjects: animal breeding; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; heterozygosity; inbreeding; mating behavior; Population genetics, reproduction patterns; sexual reproduction; Theories and miscellaneous
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/BF00289187

General recursion formulae for the coefficient of inbreeding under a cyclical mating system were derived in which one male and one female are selected from each of the n families per generation (population size N = 2 n). Each male is given the family number of his sire in each generation, while his mate comes from another family, varying systematically in different generations. Males of the r-th family in generations 1, 2, 3,..., t' = n-1 within each cycle mate with females from families r+1, r+2, r+3,..., r+t' to produce generations 2, 3, 4,..., t'+1=1, respectively. The change in heterozygosity shows a cyclical pattern of rises and falls, repeating in cycles of n-1 generations. The rate of inbreeding oscillates between 6% in different generations within each cycle, irrespective of the population size. The average rate of inbreeding per generation is approximately 1/[4 N-(Log2N+1)], which is the rate for the maximum avoidance of inbreeding. The average inbreeding effective population size is approximately 2 N-2.