Common use of Breeding Clause in Contracts

Breeding. Different combinations of genotype from the ephrin B2-/- colony were used for experiments: fully floxed (i.e. both ephrin B2 alleles floxed) and cre positive were used as experimental mice and are referred to as ephrin B2-/-, wild-type (i.e. neither ephrin B2 alleles floxed) and cre positive were used as controls for some experiments, and fully floxed and cre negative were used as controls for other experiments. For maintenance of the ephrin B2-/- colony to ensure that all genotypes were available for experiments, two breeding pair combinations were used. Firstly for experimental ephrin B2-/- mice and wild-type controls, a heterozygous ephrin B2 (i.e. only one ephrin B2 allele floxed) cre positive male was bred with a heterozygous cre negative female. This combination gives six possible outcomes for offspring: homozygous cre positive, homozygous cre negative, heterozygous cre positive, heterozygous cre negative, wild-type cre positive or wild-type cre negative. And for maintenance of a line with no cre expression, a heterozygous cre negative male was bred with a heterozygous cre negative female. All animals were kept in specific pathogen-free animal facilities, and used in accordance with the Animals (Scientific Procedures) Act 1986. Male mice between 8 and 12 weeks of age were used in all experiments, unless otherwise specified.