Fig. 4.

Schematic diagram of a typical five-tier pig production structure implemented into the gene-flow model. Two maternal breeds, A (black, e.g., Yorkshire) and B (gray, e.g., Landrace), are crossed to create hybrid females. Hybrid sows are mated to males from a terminal breed T (white, e.g., Duroc) to produce commercial animals. The color composition in individual animals represents the relative breed contribution. Numbers next to the arrows denote selection proportions transferred into subsequent tiers. Gene editing is performed in all three breeds but limited to tier I only; genotyping of selection candidates is carried out in tiers I and II (see Methods: The Epidemiological Simulation Model for more details).