Strain Rederivation

GEAM offers rederivations of particular strains of mice or rats into Level 1 facilities on campus. Whether an investigator needs to recover a strain which previously had been cryopreserved, needs to rederive a strain from embryos/sperm shipped from a source outside the university, or a strain within the university that carries unwanted pathogens, we will work with the investigator to generate and/or collect embryos for transfer into pathogen-free pseudopregnant recipients.

Prior to rederivation, the investigator will discuss with GEAM staff the specific needs of the investigator, develop a strategy and schedule for rederivation, and discuss fees. Please contact Kathy Krentz ( or (608) 890-3785 to schedule an initial meeting.

If receiving animals from off-campus, fill out the  LAR transfer form. Animals will be shipped to the GEAM quarantine facility at MSC.

The basic steps in a rederivation project are:

  1. Generation of embryos by mating superovulated females to males or generate timed pregnant moms
  2. Collection of embryos from females or perform c-sections
  3. Transfer of aseptic embryos or pups into the Level 1 females located in the Biotechnology Center

For projects involving the rederivation of pathogen-carrying strains from within the university, these animals will be transferred to GEAM quarantine facility in MSC for superovulation. For projects involving the transfer of a strain from another university, the investigator will need to arrange the transfer of these animals into GEAM quarantine facility in MSC.

We will superovulate and dissect reproductive tracts from the animals.  We then collect the embryos from the reproductive tracts and transfer them into pseudopregant B6D2F1 (for mice) and SD (for rats) recipients.  The number of transfers completed depends on the number of good quality embryos collected.

After pups are weaned recipient moms will be screened for pathogen status by serological testing. The pups will then be transferred to the investigator as soon as serology results indicate the recipient mom is pathogen-free and the animal transfer form has been completed and approved.

For more planning info, please see the following PDF:
RARC Rodent Import 2022

Mouse or Rat Strain Rederivation, either by aseptic embryo transfer or timed mating/c-section. $715/transfer to one recipient mom
$1055 (2 recipient moms)