Colony Management Harmonization Program

The typical structure of breeding colonies for inbred strains of mice and rats at InVivos can be represented as a pyramid. The colonies are designed to avoid accidental crossbreeding, to minimize genetic drift, and to prevent the development of potentially genetically distinct sublines. At the top of the pyramid is the relatively small Foundation Colony (FC), shown here as being derived from a pair of genetically tested Common Ancestors. At the base of the pyramid is the large Production Colony (PC), and in between are the two types of expansion colonies, the Pedigreed Expansion Colony (PEC) and the Expansion Colony (EC).

 pyramid-large (edit)


The FC is the only self-perpetuating colony (i.e., it produces its own new breeders), and all matings are brother x sister (BxS). The pedigreed expansion colony is an extension of the Foundation Colony and receives all of its breeders from it; all matings in the PEC are also BxS. The PEC produces breeders for the Expansion Colony (EC) utilizing once again BxS matings. The EC produces breeders for the Production Colony (PC), where random mating is utilized to scale up breeding for production of animals that will be shipped to customers. Consequently, inbred mice or rats obtained from InVivos’ PC are typically not more than four BxS generations removed from the foundation colony.

This Taconic standard pyramid management plan minimizes the risk of subline development even when multiple PCs are maintained at geographically distinct production sites. This strain harmonization is evident for InVivos where we have our own PECs, but standard operating procedures require that each of these sites receive a new PEC from Taconic US every two years (approximately every four generations). Thus, no animal supplied from InVivos can be more than 10 BxS generations removed from the strain’s current Foundation Colony, which, at present, is housed in the Germantown Gnotobiotic Center. A similar strain harmonization program is currently being implemented for Taconic Europe, in Denmark.

The pyramid colony-management program, combined with these geographic harmonization practices, assures InVivos’ customers, for example, that a B6/NTac purchased from Singapore’s production facility is as similar as possible to a B6/NTac purchased from Taconic production facilities worldwide.