AALAS Laboratory Animal Technician (LAT) Practice Test

Rederivation is a method to produce a pathogen-free line by transferring embryos from a donor, potentially infected or carrying unknown pathogens, into a pathogen-free recipient dam. The embryos are collected from the donor and implanted into a clean female that has been screened and cleared of the pathogens of concern. The offspring grow up free of those infections, effectively removing the pathogens from the lineage while preserving the donor’s genetics. This approach is widely used when bringing animals from outside sources into a clean colony to prevent disease transmission and ensure reliable research results. The other terms describe different biological processes: recombination is DNA rearrangement, replication is DNA copying, and in vitro fertilization is fertilization outside the body, not the embryo transfer into a pathogen-free dam.