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Speed Congenics

Marker-assisted backcross strategy

Figure 3: Marker-assisted backcross strategy

Microsatellite marker-assisted backcrossing allows for >99% recipient genome content to be reached after five generations (N5), thereby reducing the time frame for derivation of a congenic strain to 12-14 months (“speed congenics”). At backcross generations N2-N4, 10 mutation-carrying males are subjected to full autosomal genome scans using 96 polymorphic microsatellite markers. (Note that the X and Y chromosomes become fixed without selection as a consequence of the breeding scheme.) Two to three animals with the highest recipient genome content are selected as breeders for the next generation. At the N5 generation, males and females with near-100% recipient genome content may be intercrossed to generate homozygous congenics.

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