Colony Monitoring and History

NIA mice and rats are monitored on a regular basis to detect genetic changes that could result from contamination. Colony animals are also monitored quarterly for pathology and evidence of pathogens. The results of the health monitoring for animals in the same room as your shipment will be sent with every animal shipment. Health summaries are available for download (NIA Rodent Colony Health Summaries). If your institution has specific health status requirements, health reports should be reviewed before placing the order, and acceptable barriers specified in the special instructions section of the order form. Please note that some of the barriers housing NIA colonies are positive for Helicobacter. If your facility requires animals be from a Helicobacter-free barrier, you must make that request when you submit your order.

Inbred and hybrid mice in this NIA colony were derived from NIH pedigreed breeding stock in 1974 and for many years were maintained as closed inbred colonies. As mutations occur in both the NIA colony and the NIH breeding colonies, the NIA and NIH genotypes would undoubtedly drift apart. The solution to this problem is to periodically rederive NIA substrains from a common pedigreed breeding stock. One disadvantage to this procedure is that if the rederivation occurs in the middle of an ongoing research project, some differences in genotype of animals used early and late in the project may be unavoidable. Whether these differences pose a research problem or not is largely a matter of chance, depending upon whether significant mutations have occurred and which genetic loci are involved.

Since the problems of substrain differentiation are more significant to NIA programs as a whole, NIA initiated a policy of rederivation from pedigreed stock every 6-7 years. This rederivation interval should keep substrain differentiation at a minimum and still minimize potential disruption of ongoing research. The first rederivation of the NIA mouse colonies occurred in 1983, with subsequent rederivations in 1990, 1998, and 2005. The 1990, 1998 and 2005 rederivations used Jackson Laboratory stock.

The Fischer 344 rat colony was rederived in 1990 using Harlan Sprague Dawley Inc.'s commercial pedigreed stock that had been rederived from NIH stock in 1988, and again in 1998 and 2005 using NIH stock. Due to problems with the NIH stock received in 2005, an interim colony was developed from Taconic commercial F344 stock. This line is designated Taconic line 7068. The colony derived from NIH stock, actually cryopreserved embryos from the 1998-rederived NIA colony (Taconic line 7181), will be available by spring 2008. For dates of birth of 12/07 and early 2008, the F344 rats shipped will likely be from the Taconic commercial foundation stock. When the NIA stock derived colony is at full strength, the colony derived from Taconic commercial stock will be discontinued. These rats were also derived from NIH stock but from earlier generations - Taconic received breeders at F143 from the NIH Animal Genetic Resource in 1984. The rats were refreshed at F173 by crossing rats received from the NIH Genetic Resource in 1997 to preserve genetic continuity. The Taconic foundation colony was at F190 in 2005. All F344 rats in the NIA aging colony are located in the same barriers and subject to the same health and genetic monitoring.

In September 1985, a colony of Brown Norway (BN) rats and the F1 hybrids of the F344 X BN cross was established to provide an alternative model to the Fischer 344, based on studies that showed the F344 x BN cross produced progeny with fewer detrimental pathologies than inbred strains. Rederivation of this colony occurred in 1992 and again in 1999, using BN/BiRij stock originating from TNO, The Netherlands, and F344 stock from the NIH. The last rederivation was in 2005, using stock from the NIH for both strains.

The Caloric Restricted colony currently includes three rat genotypes and two mouse genotypes maintained under conditions similar to our other colonies except that they are individually caged. Ad libitum-fed controls maintained under the same conditions as restricted animals are also available. The rats were originally derived from NIH stock, and the colony was rederived in 1998 and again in 2005, using NIH stock for both rat strains. The mice in the caloric restricted colony were rederived in 1998 and in 2005 using stock from The Jackson Laboratory.