Cryopreservation is an integral part of the large scale mouse production and phenotyping programme, the mouse genetics project (MGP) at the Wellcome Trust Sanger Institute.With the creation of over 200 mutant mouse lines a year which are then rapidly bred and assigned to phenotyping pipelines;cryopreserving safeguards colonies whilst removing live mouse colonies from the shelf.This maintains the flow of new mutant lines coming into the process and allows for distribution to the wider research community.