Fig. 1: Stochastic effects in breeding.
a, Top: Mendelian model of the outcome of a single breeding of two heterozygous animals. + and − denote different gene alleles occurring with probabilities q and p, respectively. Theoretical frequencies of the +/+, +/− and −/− offspring are q2, 2pq and p2. Bottom: an outcome of single breeding is depicted as a random draw from the theoretical distribution above. b, Probability that out of six offspring exactly X animals will have the desired −/− genotype, given the probability c = p2 of the −/− genotype is 0.25 or 0.2. c, Example of the number of animals born out of a single breeding when taking into account fertility: there is a non-zero chance that 0 animals are born (1 − fertility). d, Distribution of −/− animals born for a genotype frequency of 0.25, for 10 (gray) or 3 (light gray) breedings, respectively.
