To assess the postnatal viability, sub-viability, and lethality of homozygous mice during cohort production.
- Monitor genotypes of Het X Het breeding units; score genotypes of at least 28 live pups, unless four or more hom pups are produced before this threshold is reached. (if other breeding strategies are used specify in the metadata and follow this convention HomXHet FemaleXMale)
- Definition of female age: "Female age earliest start/Female age oldest end" age of the youngest and oldest female mouse respectively when cohort breeding starts
- Age to be genotyped: P1-P28
- Record sex ratios of pups
- Collect and report all litters and genotype data: flag strains that produce no homozygote pups
- Identify and score lethals (defined as no homozygotes at genotype)
- Identify subviables (defined as <50% of expected homozygotes)
- If homozygous lethal: perform the embryonic lethal pipeline (if available)
1. Monitor pup number, genotypes and sex ratios of Het X Het intercrosses set to generate cohorts for phenotyping. Score at least 28 live pups when genotyped, unless four or more hom pups are produced before this threshold is reached.
2. Identify strains that produce no homozygous/hemizygous male or female pups.
a. Strains that produce NO homozygous pups will be considered LETHAL (complete preweaning lethality [MP: 0011100]).
b. X-linked strains that produce NO hemizygous male pups and NO female homozygous pups will be considered LETHAL (complete preweaning lethality [MP: 0011100]).
c. These will undergo embryonic lethal pipeline (if available)
3. Identify strains that produce less than normal numbers of homozygous/hemizygous male or female pups.
a. Strains that produce <50% expected (#totalpups * 0.125 (3 for 28) (4 for 29-36) (5 for 37-52) (See stats table in Notes)) homozygous pups will be considered SUBVIABLE (partial preweaning lethality [MP: 0011110]).
b. X-linked strains that produce <50% expected (#total pups* 0.125 (3 for 28) (4 for 29-36) (5 for 37-52) (See stats table in Notes)) hemizygous male pups and female homozygous pups will be considered SUBVIABLE (partial preweaning lethality [MP: 0011110]).
c. Some centers will proceed with secondary screening.
4. For lethal and subviable strains, heterozygous progeny will be sent for adult phenotyping.
All genotypes should be collected using validated assays.
Line level calls will be rejected until 28 mice have been genotyped, unless four or more hom pups are produced before this threshold is reached, in which case a viable call is valid.
Sub-viable significance table:
|Number genotyped||Pups observed||Formula (Excel)||P-value|